PD-L1+ monocytes/macrophages present in the stroma of HCC tumours have been shown to bind PD-1+ tumour infiltrating cytotoxic T cells and impair their proliferation, activation, and expression of proinflammatory cytokines (e.g., IL-2, IFN-γ), thus suppressing cytotoxic responses and promoting tumour evasion and progression [167]. This evidence concerns the gene CD274 and hepatocellular carcinoma.