The transcription factor STAT5A, a principal downstream effector of BCR::ABL1, has emerged as a key transcriptional regulator implicated in the development of TKI resistance. This study aims to functionally validate the role of STAT5A in TKI-resistant CML by employing CRISPR/Cas9-mediated gene knockout and assessing the downstream molecular and phenotypic alterations. Here, STAT5A is linked to chronic myelogenous leukemia, BCR-ABL1 positive.