PDCD1 and gastric cancer: For the treatment of patients with recurrent, locally advanced, or metastatic gastric or gastroesophageal junction cancer (GC/EGJC), whose tumors express PD-L1 by immunohistochemistry (IHC), the Food and Drug Administration (FDA) approved the use of pembrolizumab (anti-PD-1 antibody) in September 2017 [8].