Following lymphocyte-depleting chemotherapy, the replicated T cells are then administered to the patient (Figure 2).23–27 The first CAR T-cell therapies included tisagenlecleucel and axicabtagene ciloleucel, approved in 2017 for lymphoblastic leukemia and advanced lymphoma.23–34 The Food and Drug Administration-approved CAR T-cell therapies target CD19, a protein expressed on the surface of both malignant and normal B lymphocytes. This evidence concerns the gene CD19 and acute lymphoblastic leukemia.