CD19 and acute lymphoblastic leukemia: Although various CAR-T-cell platforms targeting CD19 have demonstrated impressive remission rates for the treatment of relapsed/refractory acute lymphoblastic leukemia (ALL), diffuse large B-cell lymphoma (DLBCL), and mantle cell lymphoma (MCL), for example [4], there are a few outstanding challenges for the engineering of autologous CAR-T cells, which limit its general use [5].