However, whether addition of ruxolitinib to chemotherapy under evaluation in current clinical trials (NCT02723994, NCT03571321) will decrease relapse risk for patients with CRLF2-rearranged/JAK pathway mutant Ph-like ALL and what resistance mechanisms may develop in JAKi-treated patients remain major knowledge gaps [3]. The gene discussed is CRLF2; the disease is acute lymphoblastic leukemia.