CD19 and acute lymphoblastic leukemia: This research has already resulted in the Food and Drug Administration (FDA) approvals of blinatumomab (CD19 bi-specific T-cell engager [BiTE]; approved in 2014), inotuzumab ozogamicin (antibody–drug conjugate targeting CD22; approved in 2017), and two CARTs (tisagenlecleucel approved in 2017; brexucabtagene autoleucel approved in 2021) as ALL salvage therapies [4–7].