There are currently four CD19 CAR T products that are FDA approved: tisagenlecleucel (Kymriah), which was approved in 2017 and is the only product to be approved for R/R pediatric B-ALL; axicabtagene ciloleucel (Yescarta), which was also approved in 2017 for R/R B-cell lymphoma in adults; brexucabtagene autoleucel (Tecartus), which was approved in 2020 for R/R B-ALL in adults and is the sole CAR T therapy approved for R/R mantle cell lymphoma; and lisocabtagene maraleucel (Breyanzi), which was approved in 2021 for R/R B-cell lymphoma in adults [35]. Here, CD19 is linked to precursor B-cell acute lymphoblastic leukemia.