Phase III trial results reported in The Lancet indicate that immune checkpoint inhibition with nivolumab (a monoclonal antibody against PD1) could be a new treatment option for advanced gastric or gastro-oesophageal junction cancer. In the ATTRACTION-2 study, 493 patients with advanced gastric or gastro-oesophageal junction cancer who were refractory to, or intolerant of, two or more previous chemotherapy regimens were enrolled from across 49 clinical centres in Japan, South Korea and Taiwan. Patients were then randomly assigned to receive either nivolumab (n = 330) or placebo (n = 193). Median overall survival (5.26 months versus 4.14 months; P < 0.0001) and 12-month overall survival rates (26.2% versus 10.9%) were higher in the nivolumab group than in the placebo group.