These drugs, including anti–cytotoxic T-lymphocyte antigen 4 (CTLA-4) antibodies and anti–programmed cell death-1 (anti-PD-1)/programmed cell death ligand-1 (PD-L1) antibodies, reactivate the anti-tumor immunity of T cells [10, 11]. The gene discussed is PDCD1; the disease is neoplasm.