Schemas demonstrating how ultrasound-mediated BBBD delivers antibodies, CAR T cells, and APCs to the tumor microenvironment for immune activation and improved tumor-cell killing. A, Anti–PD-1 delivered through an open BBB blocks immune exhaustion of effector T cells, thereby enabling T cells to exert an effector response through perforin and/or granzyme B. B, Compared with CAR T cells administered alone, ultrasound-administered CAR T cells can infiltrate the tumor microenvironment more diffusely and with longer persistence, thereby triggering tumor cytotoxicity through the CARs. C, Ultrasound BBB opening allows CXCL10 APCs and T cells to infiltrate the tumor microenvironment. Secondary to the APC presenting antigens to the T-cell, the T-cell becomes activated and thus can mediate direct tumor killing because the T cells have not been chronically stimulated.