Not meeting diagnostic criteria for myeloproliferative neoplasms (specifically, exclusion of BCR::ABL1 fusion), myeloid neoplasms with eosinophilia and defining gene rearrangement, CMML, or myelodysplastic/myeloproliferative neoplasm with SF3B1 mutation and thrombocytosis. The gene discussed is SF3B1; the disease is chronic myelomonocytic leukemia.