Relationship between clonal monocytosis of clinical significance, oligomonocytic CMML, and overt CMML. The number of monocytes reflects monocytic proliferation, whereas myelodysplasia is represented by neutrophils with hypogranulated cytoplasm and bilobed nucleus. Somatic mutations in genes like TET2, SRSF2, ASXL1, NRAS, KRAS, CBL, or SETBP1 represent the common thread of these chronic myeloid neoplasms, whereas epigenetic factors may be responsible for the phenotypic variability. Professional illustration by Patrick Lane, ScEYEnce Studios.