ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive: Among them, SIAIS562055 emerged as a potent SOS1 PROTAC, exhibiting efficacy against not only KRAS-mutant cancer but also BCR–ABL–driven CML, both in vitro and in vivo, with evidence of robust and durable SOS1 degradation and downstream signal inhibition.