Similarly, the KEYNOTE-590 study demonstrated that pembrolizumab, another anti-PD-1 antibody, plus chemotherapy improved overall survival in advanced esophageal and GEJ adenocarcinoma compared to chemotherapy alone in patients with high CPS scores.37 These results were corroborated by the KEYNOTE-859 study which focused on locally advanced or metastatic HER2-negative gastric or GEJ adenocarcinoma.105 In this study, overall survival was higher in patients with high CPS scores who received pembrolizumab. Here, PDCD1 is linked to gastroesophageal junction adenocarcinoma.