Cancer cells and immunosuppressive cells (such as tumor-associated macrophages and myeloid-derived suppressor cells) produce factors, such as IL-10 and TGF-β, (6) and express checkpoint ligands (e.g. PD-L1) that inhibit T-cell activation and proliferation, leading to T-cell dysfunction and exhaustion and reducing their cytotoxicity (7). Here, TGFB1 is linked to cancer.