In patients with unresectable or metastatic HER2-positive G/GEJ adenocarcinoma, pembrolizumab in combination with trastuzumab and chemotherapy significantly improved the ORR compared to placebo in combination with trastuzumab and chemotherapy, according to an interim analysis of the KEYNOTE-811 trial [63]. Here, ERBB2 is linked to gastroesophageal junction adenocarcinoma.