TGFB1 and neoplasm: Furthermore, the cytolysis activity of CD8+ T cells is suppressed by immunosuppressive cells infiltrating TME, including tumor-associated macrophages (TAMs), regulatory T cells (Tregs), and myeloid-derived suppressor cells (MDSCs); they secrete transforming growth factor-β (TGF-β), IL-6, and other cytokines [6].