The most common CAR T cells target CD19, being the result of 10 years of research and innovation, thus, five CAR T cell therapies are now approved by the US Food and Drug Administration (FDA) and European Medicines Agency (EMA), targeting B‐cell lymphomas, multiple myeloma and acute B‐cell lymphoblastic leukaemia, while CAR T cells against solid tumours showed inconsistent results.36, 37, 38, 39, 40. The gene discussed is CD19; the disease is precursor B-cell acute lymphoblastic leukemia.