PDCD1 and neoplasm: Among them, tumor-infiltrating DCs, NK, M1 TAMs, and N1 TANs are beneficial to anti-tumor immunity and are associated with better prognosis in GC, whereas M2 TAMs, MDSCs, N2 TANs, eTregs, and Bregs and the expressions of PD-1, CTLA-4, LAG-3, TIM-3, and TIGIT on various immune cells can promote immune escape and are associated with poor prognosis in GC.