CD4 and glioblastoma: Amoozgar et al. (2021) demonstrated that the use of αGITR promotes the differentiation of CD4+ regulatory T cells into CD4+ effector T cells and induces an effective anti-tumor response through amelioration of regulatory T cell-mediated suppression. Importantly, the use of αGITR and αPD1 antibodies proved synergistic and increased survival in three models of GBM (Amoozgar et al., 2021).