Currently, anti-programmed cell death protein 1 antibody (PD-1) alone (nivolumab or pembrolizumab) or in combination with anti-cytotoxic T-cell antigen 4 antibody (CTLA-4) is the main treatment for advanced melanoma because of its favorable clinical efficacy, as shown in recent global phase III clinical trials (12, 13). The gene discussed is PDCD1; the disease is melanoma.