PDCD1 and neoplasm: Recent advances in tumor immunotherapies aimed at reinvigorating tumor-infiltrating T cells have demonstrated clinical benefits in NSCLC, particularly with immune checkpoint blockade (ICB) treatment, including anti-programmed cell death protein-1 (PD-1)/PD-1 ligand-1 (PD-L1) and anti-cytotoxic T lymphocyte-associated antigen 4 (CTLA4) monoclonal antibody treatments.