CD4 and glioblastoma: Mechanisms of immune evasion in GBM include the tumor’s and TME’s expression of inhibitor proteins targeting CD4+ and CD8+ T cells, B and NK cells, the recruitment of immunosuppressive regulatory T cells and myeloid-derived suppressor cells, as well as the production of immunosuppressive cytokines that induce rapid T cell exhaustion and reduced T cell survival [8,10,11,17].