CD19 and acute lymphoblastic leukemia: The first CD19-directed CAR T-cell therapy approved by the U.S. Food and Drug Administration (FDA) was tisagenlecleucel (tisa-cel), initially for pediatric and young adult patients with acute lymphoblastic leukemia (ALL) based on the ELIANA trial, and subsequently for diffuse large B-cell lymphoma (DLBCL), high-grade B-cell lymphoma, and DLBCL transformed from follicular lymphoma as demonstrated in the JULIET trial [35,36,37].