TGFB1 and neoplasm: Within the TME, myeloid-derived suppressor cells (MDSCs), TAMs, tumor-associated neutrophils (TANs), Tregs, Bregs, and mature regulatory dendritic cells (mregDCs), collectively suppress cytotoxic lymphocytes through PD-1/PD-L1 and CTLA-4 engagement and by secreting IL-10, TGF-β, and VEGF.