The anti‐tumor efficacy of BAFF‐R CAR T cells has been observed in both ex vivo primary tumor co‐incubation assays and in vivo xenograft models using some of these same cell lines, leading to the initiation of a phase I clinical trial for R/R ALL patients (NCT04690595).34, 35. This evidence concerns the gene TNFRSF13C and acute lymphoblastic leukemia.