Based on the better understanding of the cellular composition and their crosstalk in tumors in recent years, novel therapeutic targets like PD-L1 (programmed death one ligand-1), PD-1 (programmed cell death protein 1), FGFR2 (fibroblast growth factor receptor 2), and et al., are emerging to prolong the prognosis of gastric cancer patients (Vrána et al., 2018; Xie et al., 2019; Zeng et al., 2019). Here, PDCD1 is linked to gastric cancer.