Since endothelial ICAM-1 and VCAM-1 expression preferentially promotes leukocyte adhesion and facilitates early steps in leukocyte extravasation across brain endothelial cells [46–48], we next used this model to assess CAR-T cell extravasation and post-BBB cytotoxicity on U87vIII cells in a blood–brain-tumor barrier (BBTB) transwell model. Here, ICAM1 is linked to neoplasm.