BCR‐ABL1 and IKZF1 deletion are strongly linked and co‐occur in 70%–80% of Ph‐ALL patients, influencing the mechanism underlying drug resistance in Ph‐ALL [20, 21]; additionally, in Ph‐ALL, IKZF1 deletions are further enriched at relapse with subclone or de novo acquisitions [22, 23]. The gene discussed is IKZF1; the disease is acute lymphoblastic leukemia.