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  <xs:element name="UnlabeledAbstract7" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_UnlabeledAbstract7"/>
  <xs:element name="UnlabeledAbstract8" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_UnlabeledAbstract8"/>
  <xs:element name="UnlabeledAbstract9" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_UnlabeledAbstract9"/>
  <xs:element name="LiabilitiesAbstract0" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_LiabilitiesAbstract0"/>
  <xs:element name="CostBasisAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_CostBasisAbstract"/>
  <xs:element name="AccumulatedAmortizationAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_AccumulatedAmortizationAbstract"/>
  <xs:element name="SubscriptionAgreementLiabilityNoncurrent" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="onco_SubscriptionAgreementLiabilityNoncurrent"/>
  <xs:element name="NotesPayableNetOfDebtDiscount" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item" id="onco_NotesPayableNetOfDebtDiscount"/>
  <xs:element name="ChangeInFairValueOfSubscriptionAgreementLiability" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="onco_ChangeInFairValueOfSubscriptionAgreementLiability"/>
  <xs:element name="ChangeInPensionBenefitObligation" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="onco_ChangeInPensionBenefitObligation"/>
  <xs:element name="StockIssuedDuringPeriodValueOfssuanceOfCommonStockAndWarrants" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="onco_StockIssuedDuringPeriodValueOfssuanceOfCommonStockAndWarrants"/>
  <xs:element name="StockIssuedDuringPeriodSharesIssuanceOfCommonStockAndWarrants" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_StockIssuedDuringPeriodSharesIssuanceOfCommonStockAndWarrants"/>
  <xs:element name="StockIssuedDuringPeriodValueIssuanceofCommonStockandWarrantsinPrivatePlacement" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="onco_StockIssuedDuringPeriodValueIssuanceofCommonStockandWarrantsinPrivatePlacement"/>
  <xs:element name="StockIssuedDuringPeriodSharesIssuanceOfCommonStockAndWarrantsInAugustPrivatePlacementNet" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_StockIssuedDuringPeriodSharesIssuanceOfCommonStockAndWarrantsInAugustPrivatePlacementNet"/>
  <xs:element name="ExerciseOfPrefundedWarrants" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="onco_ExerciseOfPrefundedWarrants"/>
  <xs:element name="ExerciseOfPrefundedWarrantsinShares" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_ExerciseOfPrefundedWarrantsinShares"/>
  <xs:element name="PurchaseOfTreasuryShares" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="onco_PurchaseOfTreasuryShares"/>
  <xs:element name="PurchaseOfTreasurySharesinShares" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_PurchaseOfTreasurySharesinShares"/>
  <xs:element name="IssuanceOfCommonStockFromExerciseOfPreferredInvestmentOptions" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="onco_IssuanceOfCommonStockFromExerciseOfPreferredInvestmentOptions"/>
  <xs:element name="StockIssuedDuringPeriodValueIssuanceOfCommonStockFromExerciseOfPreferredInvestmentOptionsinShares" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_StockIssuedDuringPeriodValueIssuanceOfCommonStockFromExerciseOfPreferredInvestmentOptionsinShares"/>
  <xs:element name="StockIssuedDuringPeriodValueIssuanceOfSeriesAPreferredStock" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="onco_StockIssuedDuringPeriodValueIssuanceOfSeriesAPreferredStock"/>
  <xs:element name="StockIssuedDuringPeriodSharesIssuanceOfSeriesAPreferredStockinShares" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_StockIssuedDuringPeriodSharesIssuanceOfSeriesAPreferredStockinShares"/>
  <xs:element name="StockIssuedDuringPeriodValueIssuanceOfCommonStockAndSeriesBPreferredStockInConnectionWithPMXTransaction" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="onco_StockIssuedDuringPeriodValueIssuanceOfCommonStockAndSeriesBPreferredStockInConnectionWithPMXTransaction"/>
  <xs:element name="StockIssuedDuringPeriodSharesIssuanceOfCommonStockAndSeriesBPreferredStockInConnectionWithPMXTransaction" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_StockIssuedDuringPeriodSharesIssuanceOfCommonStockAndSeriesBPreferredStockInConnectionWithPMXTransaction"/>
  <xs:element name="StockIssuedDuringPeriodValueAssumptionOfStockbasedCompensationPlanAwardsInConnectionWithPMXTransaction" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="onco_StockIssuedDuringPeriodValueAssumptionOfStockbasedCompensationPlanAwardsInConnectionWithPMXTransaction"/>
  <xs:element name="StockIssuedDuringPeriodSharesAssumptionOfStockbasedCompensationPlanAwardsInConnectionWithPMXTransaction" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_StockIssuedDuringPeriodSharesAssumptionOfStockbasedCompensationPlanAwardsInConnectionWithPMXTransaction"/>
  <xs:element name="OtherComprehensiveIncomeLossForeignCurrencyTranslationsAdjustmentTax" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_OtherComprehensiveIncomeLossForeignCurrencyTranslationsAdjustmentTax"/>
  <xs:element name="StockIssuedDuringPeriodValueOfChangesInPensionBenefitObligation" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="onco_StockIssuedDuringPeriodValueOfChangesInPensionBenefitObligation"/>
  <xs:element name="IssuanceOfCommonStockInInitialPublicOfferingNet" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="onco_IssuanceOfCommonStockInInitialPublicOfferingNet"/>
  <xs:element name="IssuanceOfCommonStockAndWarrantsInAprilPrivatePlacementNet" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="onco_IssuanceOfCommonStockAndWarrantsInAprilPrivatePlacementNet"/>
  <xs:element name="IssuanceOfCommonStockAndWarrantsInPrivatePlacementNet" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="onco_IssuanceOfCommonStockAndWarrantsInPrivatePlacementNet"/>
  <xs:element name="GainLossOnRelatedPartyReceivable" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item" id="onco_GainLossOnRelatedPartyReceivable"/>
  <xs:element name="ReceivableFromRelatedParties1" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="onco_ReceivableFromRelatedParties1"/>
  <xs:element name="PaymentsForPurchaseOfTreasuryShares" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="onco_PaymentsForPurchaseOfTreasuryShares"/>
  <xs:element name="EffectOfBusinessCombination" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="onco_EffectOfBusinessCombination"/>
  <xs:element name="RecognitionOfContingentWarrantLiabilityUponIssuanceOfCommonStockInPrivatePlacement" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="onco_RecognitionOfContingentWarrantLiabilityUponIssuanceOfCommonStockInPrivatePlacement"/>
  <xs:element name="WarrantsIssuedForSettlementOfContingentWarrants" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="onco_WarrantsIssuedForSettlementOfContingentWarrants"/>
  <xs:element name="DeferredOfferingCostsPreviouslyPrepaid" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="onco_DeferredOfferingCostsPreviouslyPrepaid"/>
  <xs:element name="Exerciseofprefundedwarrants" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item" id="onco_Exerciseofprefundedwarrants"/>
  <xs:element name="IssuanceOfRestrictedStock" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="onco_IssuanceOfRestrictedStock"/>
  <xs:element name="RestrictedStockForfeitures" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="onco_RestrictedStockForfeitures"/>
  <xs:element name="PaymentOfAccruedBonusThroughRelatedPartyReceivable" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="onco_PaymentOfAccruedBonusThroughRelatedPartyReceivable"/>
  <xs:element name="SignificantAgreementsTextBlock" type="dtr:textBlockItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_SignificantAgreementsTextBlock"/>
  <xs:element name="SubscriptionAgreementDisclosureTextBlock" type="dtr:textBlockItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_SubscriptionAgreementDisclosureTextBlock"/>
  <xs:element name="AcquisitionsPolicyTextBlock" type="dtr:textBlockItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_AcquisitionsPolicyTextBlock"/>
  <xs:element name="TreasuryStockPolicyPolicyTextBlock" type="dtr:textBlockItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_TreasuryStockPolicyPolicyTextBlock"/>
  <xs:element name="ScheduleOfValuationOfTheContingentWarrantLiabilityTableTextBlock" type="dtr:textBlockItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_ScheduleOfValuationOfTheContingentWarrantLiabilityTableTextBlock"/>
  <xs:element name="ScheduleOfFairValueOfOptionsGrantedIn2023And2022TableTextBlock" type="dtr:textBlockItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_ScheduleOfFairValueOfOptionsGrantedIn2023And2022TableTextBlock"/>
  <xs:element name="ScheduleOfAccompanyingConsolidatedBalanceSheetTableTextBlock" type="dtr:textBlockItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_ScheduleOfAccompanyingConsolidatedBalanceSheetTableTextBlock"/>
  <xs:element name="SummaryofSignificantAccountingPoliciesDetailsScheduleofFairValueofFinancialInstrumentsMeasuredonaRecurringBasisTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:hypercubeItem" id="onco_SummaryofSignificantAccountingPoliciesDetailsScheduleofFairValueofFinancialInstrumentsMeasuredonaRecurringBasisTable"/>
  <xs:element name="SummaryofSignificantAccountingPoliciesDetailsScheduleofFairValueofFinancialInstrumentsMeasuredonaRecurringBasisLineItems" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_SummaryofSignificantAccountingPoliciesDetailsScheduleofFairValueofFinancialInstrumentsMeasuredonaRecurringBasisLineItems"/>
  <xs:element name="ReclassificationToEquity" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="onco_ReclassificationToEquity"/>
  <xs:element name="PrepaidsResearchAndDevelopment" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item" id="onco_PrepaidsResearchAndDevelopment"/>
  <xs:element name="PrepaidProfessionalFees" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item" id="onco_PrepaidProfessionalFees"/>
  <xs:element name="FiniteLivedIntangibleAssetCost" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item" id="onco_FiniteLivedIntangibleAssetCost"/>
  <xs:element name="ImpairmentOfIntangibleAssetExcludingGoodwill" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item" id="onco_ImpairmentOfIntangibleAssetExcludingGoodwill"/>
  <xs:element name="FiniteLivedIntangibleAssetsAccumulatedAmortizationEffectOfCurrencyTranslation" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="onco_FiniteLivedIntangibleAssetsAccumulatedAmortizationEffectOfCurrencyTranslation"/>
  <xs:element name="AccruedResearchAndDevelopmentCurrent" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="onco_AccruedResearchAndDevelopmentCurrent"/>
  <xs:element name="AccruedDeferredOfferingCosts" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="onco_AccruedDeferredOfferingCosts"/>
  <xs:element name="AssetAcquisitionConsiderationTransferredInventory" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="onco_AssetAcquisitionConsiderationTransferredInventory"/>
  <xs:element name="AssetAcquisitionConsiderationTransferredENTADFIIntangible" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="onco_AssetAcquisitionConsiderationTransferredENTADFIIntangible"/>
  <xs:element name="AcquisitionsDetailsScheduleofEstimatedFairValuesofAssetsAcquiredandLiabilitiesTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:hypercubeItem" id="onco_AcquisitionsDetailsScheduleofEstimatedFairValuesofAssetsAcquiredandLiabilitiesTable"/>
  <xs:element name="AcquisitionsDetailsScheduleofEstimatedFairValuesofAssetsAcquiredandLiabilitiesLineItems" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_AcquisitionsDetailsScheduleofEstimatedFairValuesofAssetsAcquiredandLiabilitiesLineItems"/>
  <xs:element name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedRightofUseAsset" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item" id="onco_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedRightofUseAsset"/>
  <xs:element name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesCustomerRelationships" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item" id="onco_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesCustomerRelationships"/>
  <xs:element name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedProductRightsForDevelopedTechnology" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item" id="onco_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedProductRightsForDevelopedTechnology"/>
  <xs:element name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccruedExpenses" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="onco_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccruedExpenses"/>
  <xs:element name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPensionBenefitObligation" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="onco_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPensionBenefitObligation"/>
  <xs:element name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNotePayable" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="onco_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNotePayable"/>
  <xs:element name="SubscriptionAgreementDetailsScheduleofAssumptionsUsedinMonteCarloModelWhichUtilizesLevel3InputsTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:hypercubeItem" id="onco_SubscriptionAgreementDetailsScheduleofAssumptionsUsedinMonteCarloModelWhichUtilizesLevel3InputsTable"/>
  <xs:element name="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofValuationoftheContingentWarrantLiabilityTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:hypercubeItem" id="onco_ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofValuationoftheContingentWarrantLiabilityTable"/>
  <xs:element name="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofValuationoftheContingentWarrantLiabilityLineItems" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofValuationoftheContingentWarrantLiabilityLineItems"/>
  <xs:element name="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofStockOptionsTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:hypercubeItem" id="onco_ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofStockOptionsTable"/>
  <xs:element name="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofStockOptionsLineItems" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofStockOptionsLineItems"/>
  <xs:element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValueGranted" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item" id="onco_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValueGranted"/>
  <xs:element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValueForfeitedCancelled" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item" id="onco_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValueForfeitedCancelled"/>
  <xs:element name="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofFairValueofOptionsGrantedTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:hypercubeItem" id="onco_ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofFairValueofOptionsGrantedTable"/>
  <xs:element name="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofFairValueofOptionsGrantedLineItems" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofFairValueofOptionsGrantedLineItems"/>
  <xs:element name="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofUnvestedRestrictedStockTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:hypercubeItem" id="onco_ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofUnvestedRestrictedStockTable"/>
  <xs:element name="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofUnvestedRestrictedStockLineItems" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsScheduleofUnvestedRestrictedStockLineItems"/>
  <xs:element name="LicenseAgreement" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="onco_LicenseAgreement"/>
  <xs:element name="IncomeTaxReconciliationNondeductibleExpenseDerivativeLiability" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item" id="onco_IncomeTaxReconciliationNondeductibleExpenseDerivativeLiability"/>
  <xs:element name="IncomeTaxReconciliationNondeductibleExpenseOfficersCompensation" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item" id="onco_IncomeTaxReconciliationNondeductibleExpenseOfficersCompensation"/>
  <xs:element name="EffectiveIncomeTaxRateReconciliationNondeductibleExpenseStateRateAdjustment" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item" id="onco_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseStateRateAdjustment"/>
  <xs:element name="RetirementPlansDetailsScheduleofBenefitObligationandtheNetPeriodicBenefitCostTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:hypercubeItem" id="onco_RetirementPlansDetailsScheduleofBenefitObligationandtheNetPeriodicBenefitCostTable"/>
  <xs:element name="RetirementPlansDetailsScheduleofBenefitObligationandtheNetPeriodicBenefitCostLineItems" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_RetirementPlansDetailsScheduleofBenefitObligationandtheNetPeriodicBenefitCostLineItems"/>
  <xs:element name="AmortizationOfNetGain" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item" id="onco_AmortizationOfNetGain"/>
  <xs:element name="EffectOfSettlement" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item" id="onco_EffectOfSettlement"/>
  <xs:element name="DefinedBenefitPlanBenefitObligationOrdinaryContributionsPaidByEmployees" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="onco_DefinedBenefitPlanBenefitObligationOrdinaryContributionsPaidByEmployees"/>
  <xs:element name="DefinedBenefitPlanPlanAssetsOrdinaryContributionsPaidByEmployees" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item" id="onco_DefinedBenefitPlanPlanAssetsOrdinaryContributionsPaidByEmployees"/>
  <xs:element name="OrganizationandBasisofPresentationDetailsTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:hypercubeItem" id="onco_OrganizationandBasisofPresentationDetailsTable"/>
  <xs:element name="InitialPublicOfferingShares" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="instant" nillable="true" substitutionGroup="xbrli:item" id="onco_InitialPublicOfferingShares"/>
  <xs:element name="PublicOfPerShare" type="dtr:perShareItemType" abstract="false" xbrli:periodType="instant" nillable="true" substitutionGroup="xbrli:item" id="onco_PublicOfPerShare"/>
  <xs:element name="GoingConcernandManagementsPlansDetailsTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:hypercubeItem" id="onco_GoingConcernandManagementsPlansDetailsTable"/>
  <xs:element name="GoingConcernandManagementsPlansDetailsLineItems" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_GoingConcernandManagementsPlansDetailsLineItems"/>
  <xs:element name="WorkingCapitalDeficit" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="onco_WorkingCapitalDeficit"/>
  <xs:element name="SummaryofSignificantAccountingPoliciesDetailsTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:hypercubeItem" id="onco_SummaryofSignificantAccountingPoliciesDetailsTable"/>
  <xs:element name="SummaryofSignificantAccountingPoliciesDetailsLineItems" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_SummaryofSignificantAccountingPoliciesDetailsLineItems"/>
  <xs:element name="BalanceSheetDetailsDetailsTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:hypercubeItem" id="onco_BalanceSheetDetailsDetailsTable"/>
  <xs:element name="BalanceSheetDetailsDetailsLineItems" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_BalanceSheetDetailsDetailsLineItems"/>
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  <xs:element name="BusinessTransactionYeare" type="xbrli:durationItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_BusinessTransactionYeare"/>
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  <xs:element name="ImpairmentRate" type="dtr:percentItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_ImpairmentRate"/>
  <xs:element name="InitialPaymentAmount" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item" id="onco_InitialPaymentAmount"/>
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  <xs:element name="LicensedProductsPlusMilestonePaymentsDescription" type="xbrli:stringItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_LicensedProductsPlusMilestonePaymentsDescription"/>
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  <xs:element name="CashPaymentToTheSeller" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item" id="onco_CashPaymentToTheSeller"/>
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  <xs:element name="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart2LineItems" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart2LineItems"/>
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  <xs:element name="ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3LineItems" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_ConvertibleRedeemablePreferredStockandStockholdersEquityDetailsPart3LineItems"/>
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  <xs:element name="PlacementAgentFeeAndManagementFeePercentage" type="dtr:percentItemType" abstract="false" xbrli:periodType="instant" nillable="true" substitutionGroup="xbrli:item" id="onco_PlacementAgentFeeAndManagementFeePercentage"/>
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  <xs:element name="WarrantsIssuableUnderProvisionShares" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_WarrantsIssuableUnderProvisionShares"/>
  <xs:element name="IncreaseInTheFairValueOfThePreferredInvestmentOptions" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item" id="onco_IncreaseInTheFairValueOfThePreferredInvestmentOptions"/>
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  <xs:element name="FixedCommissionRate" type="dtr:percentItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_FixedCommissionRate"/>
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  <xs:element name="PercentageOfCommonStockShares" type="dtr:percentItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_PercentageOfCommonStockShares"/>
  <xs:element name="ExercisePrice" type="dtr:perShareItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_ExercisePrice"/>
  <xs:element name="GrantDateFairValueOfStockOption" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item" id="onco_GrantDateFairValueOfStockOption"/>
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  <xs:element name="CommitmentsandContingenciesDetailsTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:hypercubeItem" id="onco_CommitmentsandContingenciesDetailsTable"/>
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  <xs:element name="IncomeTaxesDetailsTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:hypercubeItem" id="onco_IncomeTaxesDetailsTable"/>
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  <xs:element name="AssetPurchaseAgreementMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_AssetPurchaseAgreementMember"/>
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  <xs:element name="August2022PrivatePlacementMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_August2022PrivatePlacementMember"/>
  <xs:element name="August2024Member" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_August2024Member"/>
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  <xs:element name="AugustWainwrightWarrantsMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_AugustWainwrightWarrantsMember"/>
  <xs:element name="BankruptcyCourtMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_BankruptcyCourtMember"/>
  <xs:element name="BusinessAcquisitionMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_BusinessAcquisitionMember"/>
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  <xs:element name="ChiefBusinessOfficerMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_ChiefBusinessOfficerMember"/>
  <xs:element name="CincinnatiChildrensHospitalMedicalCenterMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_CincinnatiChildrensHospitalMedicalCenterMember"/>
  <xs:element name="CoDevelopmentAgreementMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_CoDevelopmentAgreementMember"/>
  <xs:element name="CommonStockIssuableUponConversionOfSeriesAPreferredStockMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="onco_CommonStockIssuableUponConversionOfSeriesAPreferredStockMember"/>
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</xs:schema>
