A randomized, controlled, phase III trial (KEYNOTE-006) revealed that pembrolizumab prolonged progression-free survival (PFS) and overall survival (OS) in patients with advanced melanoma as compared with the monoclonal antibody anti-CTLA-4 drug ipilimumab, and the incidence of high-grade adverse reactions was low (18). The gene discussed is CTLA4; the disease is melanoma.