A method of identifying a cognate antigen for a T-cell receptor composed of an alpha chain (TCRα) and a beta chain (TCRβ), the method comprising: a. using a population of T-cells obtained from a patient wherein each T-cell comprises a TCR comprising TCRα and TCRβ chains; b. barcoding nucleic acids from each T-cell with a cell-specific barcode; c. sequencing the barcoded nucleic acids to obtain TCRA and TCRB gene sequences coding for the TCRα and TCRβ chains; d. identifying TCRA and TCRB genes having the same barcodes as gene pairs encoding a functional TCR; e. introducing the TCRA and TCRB gene pairs identified in step d. into a receptive T-cell; f. using a population of tumor cells from the patient each possibly comprising one or more tumor neoantigen; g. identifying tumor neoantigen genes; wherein the one or more tumor neoantigens are identified by sequencing of the nucleic acids in the tumor cell and identifying genes with non-silent mutations as neoantigen genes; h. forming neoantigen peptides from neoantigen genes identified in step g; i. combining the neoantigen peptides from step h. with an MHC-1 antigen presenting complex and an oligonucleotide barcode to form a barcoded MHC-neoantigen peptide complex; j. contacting the T-cells from step e. with the barcoded MHC-neoantigen peptide complexes from step i. to form cell-bound MHC-neoantigen-TCR complexes; k. barcoding each of the TCR genes and the MHC-neoantigen complex barcode from each T-cell from step j. with a cell-specific barcode; l. sequencing the TCR genes with associated cell-specific barcodes and the MHC-neoantigen complex barcodes associated with cell-specific barcodes in the T-cells from step k.; m. identifying the neoantigen as the cognate antigen for the TCR if at least one of the TCR genes and MHC-neoantigen complex barcode are associated the same cell-specific barcode. a. using a population of T-cells obtained from a patient wherein each T-cell comprises a TCR comprising TCRα and TCRβ chains; b. barcoding nucleic acids from each T-cell with a cell-specific barcode; c. sequencing the barcoded nucleic acids to obtain TCRA and TCRB gene sequences coding for the TCRα and TCRβ chains; d. identifying TCRA and TCRB genes having the same barcodes as gene pairs encoding a functional TCR; e. introducing the TCRA and TCRB gene pairs identified in step d. into a receptive T-cell; f. using a population of tumor cells from the patient each possibly comprising one or more tumor neoantigen; g. identifying tumor neoantigen genes; wherein the one or more tumor neoantigens are identified by sequencing of the nucleic acids in the tumor cell and identifying genes with non-silent mutations as neoantigen genes; h. forming neoantigen peptides from neoantigen genes identified in step g; i. combining the neoantigen peptides from step h. with an MHC-1 antigen presenting complex and an oligonucleotide barcode to form a barcoded MHC-neoantigen peptide complex; j. contacting the T-cells from step e. with the barcoded MHC-neoantigen peptide complexes from step i. to form cell-bound MHC-neoantigen-TCR complexes; k. barcoding each of the TCR genes and the MHC-neoantigen complex barcode from each T-cell from step j. with a cell-specific barcode; l. sequencing the TCR genes with associated cell-specific barcodes and the MHC-neoantigen complex barcodes associated with cell-specific barcodes in the T-cells from step k.; m. identifying the neoantigen as the cognate antigen for the TCR if at least one of the TCR genes and MHC-neoantigen complex barcode are associated the same cell-specific barcode.