ICIs such as anti-cytotoxic Tlymphocyte associated protein 4 (CTLA4, CTLA-4), anti-programmed cell death protein 1 (PD1, PD-1), and anti-programmed cell death one ligand 1 (PDL1, PD-L1) have been approved for the clinical application of advanced malignancies, including melanoma, non-small-cell lung cancer, urothelial carcinoma, gastric cancer, liver cancer, and Hodgkin’s lymphoma (Wei et al., 2018; Perez-Ruiz et al., 2019). Here, PDCD1 is linked to gastric cancer.