The capacity of CD19-redirected CAR-Ts for in vivo activation, expansion, and robust tumoricidal activity, which results in the mentioned high rates of disease remission even in patients with R/R B-ALL, leads to adverse events and toxicities such as cytokine release syndrome (CRS), neurologic toxicities, and B-cell aplasia (14, 24–27). This evidence concerns the gene CD19 and acute lymphoblastic leukemia.