BCR::ABL1 drives chronic myeloid leukemia (CML) pathology and treatment, as revealed by the success of tyrosine kinase inhibitor (TKI) therapy. However, additional poorly characterized molecular mechanisms, acting independently of BCR::ABL1, play crucial roles in CML, contributing to leukemic stem cells (LSCs) persistence, drug resistance and disease progression. Here, by combining high sensitive mass spectrometry (MS)-based phosphoproteomics with the SignalingProfiler pipeline, we obtained two signaling maps reporting the BCR::ABL1 dependent and independent pro-survival signalling mechanisms, respectively. Crucial oncogenic pathways were deregulated in resistant cells. To unbiasedly discover therapeutic vulnerabilities, we implemented the Druggability Score, a computational algorithm ranking proteins according to their inferred ability to kill resistant cells when suppressed. By this strategy, we identified a novel and unexpected role for FLT3 in BCR::ABL1 independent resistance. Remarkably, pharmacological suppression of FLT3 triggers death of both resistant cell lines and patients-derived LSCs. Finally, we propose midostaurin treatment as a therapeutic option to improve the clinical outcome of non responder patients and eradicate LSCs.