Immunotherapy represented by immune checkpoint inhibitors (ICIs) against PD-1/L1 and CTLA-4 presents the durable therapeutic effects for the minority of GC patients; undesirably, most patients cannot respond to it (Shitara et al., 2018; Shitara et al., 2020; Janjigian et al., 2021). Here, CTLA4 is linked to gastric cancer.