Second, antigen-presenting machinery together with the size and expression level of the antigen repertoire are determining factors for the antigenic peptide-MHC complex in tumor cells, which, with the help of activated NK cells and matured DC, lead to the generation of neoantigen-specific activated T cells expressing PD-1, CXCR3, and IFNγ. The gene discussed is PDCD1; the disease is neoplasm.