TGFB1 and neoplasm: Second, mCRPC has traditionally been described as a “cold tumor” with scarce T cell infiltration, due to an immunosuppressive tumor microenvironment (TME) comprised of tumor-associated macrophages (TAMs), myeloid-derived suppressor cells (MDSCs), T-regulatory cells (Tregs), and cytokines such as transforming growth factor beta (TGF-β) and interleukin-10 (IL-10)[46-48].