Despite the advent of inhibitors of constitutively-active BRAF (e.g., vemurafenib) and immune checkpoints (e.g., antibodies against programmed cell death protein 1 (PD-1), programmed death-ligand 1 (PD-L1) or cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), current therapies rarely provide durable responses in advanced melanoma. The gene discussed is PDCD1; the disease is melanoma.