Currently, CD19-targeting CAR T cells are the most widely used and exhibit remarkable efficacy in patients with relapsed or refractory acute lymphoblastic leukaemia (R/R ALL) and relapsed or refractory B cell non-Hodgkin lymphoma (R/R B-NHL), with a complete response (CR) rate of 82% to 93% (2–4) and 40% to 53% (5–7), respectively. The gene discussed is CD19; the disease is acute lymphoblastic leukemia.