CD19 and acute lymphoblastic leukemia: KYMRIAH TM (tisagenlecleucel), which is a second generation CAR-T cell product (4-1BB costimulatory domain) directed against CD19 antigen, was approved by the Food and Drug Administration (FDA) for ALL in 2017 based on multicenter clinical studies, which established an overall remission rate of 81% in children and young adults with relapsed/refractory acute B-cell acute lymphoblastic leukemia (r/r B-cell ALL), and a best overall response rate of 52% in adults with relapsed/refractory diffuse large B-cell lymphoma (r/r DLBCL) (Thudium Mueller et al., 2021).