In June 2024, China approved pembrolizumab in combination with trastuzumab and chemotherapy as a first‐line treatment for patients with locally advanced, unresectable, or metastatic HER2‐positive gastric or gastroesophageal junction adenocarcinoma, whose tumors express PD‐L1 CPS ≥ 1, as determined by a fully validated test. This evidence concerns the gene CD274 and gastroesophageal junction adenocarcinoma.