Combination therapy with the anti-HER2 antibody trastuzumab with pembrolizumab and chemotherapy is the current standard of care for patients with HER2-positive metastatic gastric or gastroesophageal junction cancer (G/GEJ). In this interview, Yelena Y. Janjigian, MD, Memorial Sloan Kettering Cancer Center, New York, NY, presents the initial results from KEYNOTE-811 (NCT03615326), a Phase III study evaluating trastuzumab and chemotherapy with or without pembrolizumab in patients with HER2-positive metastatic gastric or gastroesophageal junction cancer. This interview took place at the ESMO World Congress on Gastrointestinal Cancer 2021.