PDCD1 and neoplasm: In conclusion, these works demonstrate that engineering CAR T cells to secrete anti–PD1 Abs/minibodies offers a promising solution to the challenges of treating patients with GBM, overcoming dual challenges of targeting specificity (EGFRvIII or other tumor-associated antigen), and overriding PD1-PDL1 induced immunosuppression encountered in the TME, whether from tumor or other immune-infiltrating cells.