CD8A and neoplasm: Studies demonstrate that tumor-infiltrating T lymphocytes (TILs), as core TME components, form dual regulatory networks through subtype distribution and functional states: CD8+ T cells mediate tumor cell killing via the perforin-granzyme system (3), while regulatory T cells (Tregs) foster disease progression by establishing an immunosuppressive niche through IL-10/TGF-β (4–6).