The World Health Organization Classification of Hematolymphoid Tumors (WHO) and the International Consensus Classification (ICC) of 2022 introduced major changes to the definition of CMML. To assess qualitative and quantitative implications for patient care, we started with 3,311 established CMML cases (according to WHO 2017 criteria) and included also 2,130 oligomonocytosis cases fulfilling the new CMML diagnostic criteria. Applying both classification systems from 2022, 356 and 241 …