CD19 and leukemia: In particular, chimeric antigen receptors (CARs) that redirect T cells to recognize CD19 or BCMA have shown remarkable efficacy against certain types of leukemia, lymphoma, and multiple myeloma.1 So far, six CAR-T therapies have been approved by the U.S. Food and Drug Administration (FDA) since 2017, with several hundred more products at various stages of clinical development.2 CAR-T cells are also being explored for a multitude of nononcology indications, including transplant rejection, infection, autoimmunity, cardiovascular disease, fibrosis, and senescence.3–7