Currently, clinically approved agents are restricted to those targeting programmed cell death 1 (PD-1)/programmed cell death-ligand 1(PD-L1) or cytotoxic T-lymphocyte antigen 4 (CTLA4), based on various immunotherapy-related preclinical and clinical studies for CRC (18). The gene discussed is PDCD1; the disease is colorectal carcinoma.