CAR T cell therapy, in which a patient’s own immune cells are reprogrammed to recognize and kill cancer, has revolutionized the treatment of blood cancers. Unfortunately, however, a significant portion of treated patients relapse, and CAR T cell therapy for aggressive solid tumors has been largely ineffective. A major roadblock preventing this therapy from curing more patients is the gradual loss of CAR T cells’ ability to kill tumor cells, which results in tumor progression or relapse. Dr. Weber aims to develop optimized killer CAR T cells that stay in the fight against cancer. His lab has developed a novel, high-throughput method of analysis that can be used to identify T cell characteristics, genes, and other biological features that enable CAR T cells to serially kill cancer cells. These insights will provide a roadmap for reprogramming T cells with enhanced tumor killing function, paving the way for more efficacious CAR T cell therapies and potentially other cancer immunotherapies for patients in need.