In this context, immunotherapeutic agents such as blinatumomab (a bispecific T-cell engager targeting CD19), InO (an anti-CD22 antibody–drug conjugate), and daratumumab (an anti-CD38 monoclonal antibody) have shown remarkable results in R/R B-ALL, offering new perspectives in disease management. This evidence concerns the gene CD19 and acute lymphoblastic leukemia.