CD8A and hepatocellular carcinoma: MDSCs are a heterogeneous population of immunosuppressive immature myeloid cells (monocytic or granulocytic), which are abundant in the liver and increased in the peripheral blood of patients with HCC.[24], [25], [26] They promote local Treg differentiation from CD4+ T cells and suppress CD8+ T cell and natural killer (NK) cell activation through mediators such as TGFβ and arginase.27