TGFB1 and neoplasm: A specific anti‐TGF‐β1 antibody or a recently developed novel bifunctional anti‐PD‐L1/TGF‐β checkpoint inhibitor, the fusion protein M7824, decreased tumor burden and increased survival in mice through promoting CD8+ T cell and NK cell activation and blocking the immunosuppressive activity induced by the SCLC cells.24, 25