Immune checkpoint inhibitors (ICIs) targeting programmed cell death 1 (PD-1) and its ligand PD-L1 have revolutionized the treatment of various solid tumors, including non-small cell lung cancer (NSCLC) and gastric cancer (GC) (Okazaki et al., 2013; Iwai et al., 2017; Sharma et al., 2021; Alsina et al., 2022). Here, PDCD1 is linked to gastric cancer.