Another approach involves the use of truncated suppressive receptors such as a dominant-negative form of TGF-β receptor II or a dominant-negative PD-1, which shield T cells from the negative effects of TGF-β and PD-L1, respectively.118–120 Apart from the upregulation of inhibitory ligands such as PD-L1, the tumour microenvironment is additionally enriched with immunosuppressive cytokines, one of which is TGF-β. This evidence concerns the gene PDCD1 and neoplasm.