When anti-programmed cell death 1 (PD-1) inhibitors and chemotherapy are used to treat advanced gastric or gastroesophageal junction (G/GEJ) adenocarcinomas, patients with a programmed death ligand 1 (PD-L1) combined positive score of >5 have a considerably better response and longer progression-free survival (PFS). This evidence concerns the gene PDCD1 and adenocarcinoma.