To overcome this limitation, we have engineered fourth generation CPI Ab receptor-modified (ARMed) EGFRvIII CAR T cells, capable of trafficking into GBM to produce and secrete anti-PD1 Abs in situ, and evaluated them in vitro and in vivo in subcutaneous and orthotopic GBM murine models. Here, PDCD1 is linked to glioblastoma.