Two CD19-targeting CAR T-cells are currently approved by the Food and Drug Administration (FDA) and the European Medicines Agency (EMA) for the treatment of R/R B-ALL: tisagenlecleucel (CTL019) in children and young adults up to 25 years of age and brexucabtagene autoleucel (KTE-X19) in adult patients (aged more than 26 years for EMA), based on the results of the ELIANA and ZUMA-3 trials, respectively [19,20]. The gene discussed is CD19; the disease is acute lymphoblastic leukemia.