CD4 and neoplasm: Fc-optimized anti-CTLA-4 antibodies induce important quantitative and qualitative changes in tumor blood vessels that culminate in the increase of TA-HEVs, specialized blood vessels supporting lymphocyte entry into tumors, resulting in improved CD4+ and CD8+ T cell infiltration into tumors and better response to PD-1 blockade in both conventional and humanized mouse models.