PDCD1 and gastric cancer: The KEYNOTE-811 trial further showed that combining PD-1 inhibitor with trastuzumab and chemotherapy in patients with HER2-overexpressing advanced gastric cancer substantially enhanced objective response rates (74.4% vs 51.9%) and progression-free survival (hazards ratio 0.73, 95% CI 0.61‐0.87) [6, 7].