Programmed cell death 1 (PD‐1), programmed death ligand‐1 (PD‐L1) and Cytotoxic T‐lymphocyte‐associated protein‐4 (CTLA‐4) could inhibit the proliferation and differentiation of immunocompetent cells and the recognition of tumour cells by tumour‐infiltrating lymphocytes (TILs). The gene discussed is PDCD1; the disease is neoplasm.