CD4 and neoplasm: B7-H3 was initially found to be an immune co-stimulant (118), in which B7-H3-Ig induced the proliferation of CD4+ and CD8+ T cells and increased the secretion of interferon γ thereby enhancing T cell activity.B7-H3 also enhances T cell activity by promoting the production of IL-10, TGF-β1.In addition, the positive correlation between the expression of FOXP3+ tregs and B7-H3 favoring the immune system to suppress the tumor microenvironment (119, 120).