Approved CD19-CAR-T therapies show high response rates in B-ALL and B-NHL, depending on the CAR-T product, line of treatment and specific indication, with unprecedented long-term progression-free and overall survival in patients with relapsed or refractory disease (11, 12, 14–16, 32) The same holds true for B-cell maturation antigen (BCMA) directed CAR-T for MM (24, 25), but unfortunately a considerable proportion of these (high-risk) patients still relapse after or are refractory to CAR-T therapy. Here, CD19 is linked to acute lymphoblastic leukemia.