PD-1 inhibition together with anti-HER2 CAR T cells enhanced the efficacy of the CAR T therapy in a GBM cell line.99 PD-1 inhibition combined with anti-EGFRvIII CAR T cells overcame T-cell exhaustion leading to enhanced anti-tumor activity in mice.100,102 This has led to clinical trials investigating the safety and efficacy of ICIs with CAR T cells in GBM, however, the results are still to be published. This evidence concerns the gene ERBB2 and glioblastoma.