Tisagenlecleucel (tisa-cel, Kymriah©) was the first CD19 directed CAR-T therapy to be approved for the use in children and young adults with relapsed or refractory (rr) acute lymphoblastic leukemia (ALL) by the U.S. Food and Drug Administration (FDA) in 2017 (Maude et al. 2018). The gene discussed is CD19; the disease is acute lymphoblastic leukemia.