We employed PeptiCHIP Immunopeptidomics to profile tumor associated antigens (TAA) actively targeted by tumor specific T cells by exploiting the trogocytosis effect, whereby antigen presenting cells (APCs) nibble portions of the cognate T cell containing the TCR. The antigen presenting cells were then processed by Immunoaffinity purification by peptiCHIP to identify the relevant HLA-I peptides by LCMS on the Bruker Tims TOF Pro instrument.