In the phase 3 CheckMate-649 study in patients with previously untreated, unresectable, non–HER2-positive gastric, GEJ, or esophageal adenocarcinoma, nivolumab plus chemotherapy resulted in significant improvements in OS and PFS vs chemotherapy alone in patients with PD-L1 CPS ≥ 5 (primary endpoint), patients with PD-L1 CPS ≥ 1, and all randomly assigned patients, and the treatment effect was more pronounced in the CPS ≥ 5 population. The gene discussed is ERBB2; the disease is esophageal adenocarcinoma.