In a recent clinical trial, cancer patients could not obtain desirable benefit and favorable therapeutic efficacy from immunotherapy using PD-1 antibody and PD-L1 antibody treatment if tumor infiltration lymphocytes were exhausted in the TME (81–84) or if the cancer cells did not express programmed death-ligand 1 (PD-L1) (85–89). The gene discussed is PDCD1; the disease is cancer.