In 2017, the FDA approved 2 CAR T-cell therapies: tisagenlecleucel and axicabtagene ciloleucel (U.S. Food and Drug Administration, 2017; U.S. Food and Drug Administration, 2017), which are CAR T cells targeting the B-cell receptor CD19, respectively for the treatment of pediatric and young adults with relapsed/refractory B-ALL and diffuse large B-cell lymphoma (DLBCL). The gene discussed is CD19; the disease is precursor B-cell acute lymphoblastic leukemia.