Chimeric antigen receptor T cells (CAR T cells) are a promising immunotherapy approach to cancer treatment in which a patient's own immune cells attack tumors by targeting an identifying marker, or antigen, that is displayed at high levels on cancerous cells. However, CAR T cells that target a single antigen have had mixed results in clinical trials, which may be due to ongoing variability in the antigens that tumors display. In this month's issue of the JCI, a team led by Nabil Ahmed at Baylor College of Medicine demonstrated that CAR T cells that were engineered to target two different tumor antigens were more effective at controlling tumors in an animal model than typical CAR T cells, which target a single antigen. In an animal model of glioblastoma, treatment with the dual-antigen CAR T cells led to anti-tumor activity over a longer period of time and improved survival compared to treatment with single-antigen CAR T cells. These findings suggest that engineering CAR T cells to target multiple antigens on tumor cells could result in immunotherapeutic approaches with better efficacy in treating some types of cancer.