PDCD1 and neoplasm: Among these pathways, the programmed death-ligand 1 (PD-L1)/programmed cell death protein 1 (PD-1) axis and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) pathway have garnered significant attention due to their roles in immune evasion and tumor progression [8,9,10,11,12,13].