Remarkable remission rates in clinical trials using CAR T-cells directed against CD19+ B-cell malignancies led to FDA approval of the first CAR T-cell therapies for patients with relapsed/refractory acute lymphoblastic leukemia (ALL) or diffuse large B-cell lymphoma (DLBCL) and for patients with primary mediastinal B-cell lymphoma (PMBCL) in 2017. Here, CD19 is linked to acute lymphoblastic leukemia.