Due to higher proportion of FoxP3+ Tregs/CD4+ T cells and ICOS+ FoxP3+ Tregs/total FoxP3+ Tregs, their study concludes that ICOS+ FoxP3+ Tregs may be the main immunosuppressive cell type in HCC microenvironment (44–46). The gene discussed is ICOS; the disease is hepatocellular carcinoma.