Some immune check-point blockade therapies, such as those involving monoclonal antibodies targeting cytotoxic T lymphocyte associated protein 4 (CTLA-4), programmed cell death protein 1 (PD-1), and PD-1 ligand (PD-L1), resulted in T lymphocyte-mediated tumor regression in various malignancies (11–17), including gastric carcinoma (18). The gene discussed is PDCD1; the disease is gastric carcinoma.