TGFB1 and neoplasm: Different immunosuppressive cells and inhibitory factors are part of the tumor microenvironment, such as regulatory T cells (Tregs), myeloid-derived suppressor cells, tumor-associated macrophages, immunosuppressive cytokines (i.e., IL-10, TGF-B), or different ligands for tumor-expressed T cell inhibitory receptors (55, 56).