Chronic myelomonocytic leukemia (CMML) is a clonal hematopoietic stem cell disorder characterized by sustained peripheral blood monocytosis and bone marrow dysplasia, with a risk of leukemic transformation. The diagnosis is based on sustained peripheral blood monocytosis (≥0.5 × 10^9/L), consistent bone marrow morphology, low blast counts, and cytogenetic or molecular evidence of clonality. Cytogenetic abnormalities occur in about 30% of patients, while somatic mutations are present in >95%. Risk stratification models, such as the Mayo Molecular Model, help identify high-risk patients for allogeneic stem cell transplant (ASCT). Treatment options include ASCT for high-risk patients and drug therapy, primarily hypomethylating agents (HMA), which have limited efficacy and durability. Novel therapies, such as JAK/STAT inhibitors and BCL2 inhibitors, are being explored. Unique disease associations include systemic inflammatory autoimmune diseases, leukemia cutis, and lysozyme-induced nephropathy.Chronic myelomonocytic leukemia (CMML) is a clonal hematopoietic stem cell disorder characterized by sustained peripheral blood monocytosis and bone marrow dysplasia, with a risk of leukemic transformation. The diagnosis is based on sustained peripheral blood monocytosis (≥0.5 × 10^9/L), consistent bone marrow morphology, low blast counts, and cytogenetic or molecular evidence of clonality. Cytogenetic abnormalities occur in about 30% of patients, while somatic mutations are present in >95%. Risk stratification models, such as the Mayo Molecular Model, help identify high-risk patients for allogeneic stem cell transplant (ASCT). Treatment options include ASCT for high-risk patients and drug therapy, primarily hypomethylating agents (HMA), which have limited efficacy and durability. Novel therapies, such as JAK/STAT inhibitors and BCL2 inhibitors, are being explored. Unique disease associations include systemic inflammatory autoimmune diseases, leukemia cutis, and lysozyme-induced nephropathy.