Although PD-L1 upregulation occurs in approximately 40% of gastroesophageal cancers and the United States Food and Drug Administration (FDA) has approved pembrolizumab and nivolumab for patients with GC and completely resected esophageal or gastroesophageal junction cancer [24–26], preliminary clinical data with single-agent treatment with PD-1/PD-L1 inhibitors showed low response rates of only 22%-27% for metastatic gastroesophageal cancer patients with PD-L1+ expression [27]. Here, PDCD1 is linked to gastric cancer.