The most frequent CMML-associated mutations can be categorized as follows: (1) epigenetic modifiers—ASXL1, TET2, DNMT3A, IDH1, IDH2, and UTX [22,23,24,25]; (2) RNA splicing factors—SRSF2, SF3B1, U2AF1, and ZRSR2 [26,27]; (3) cell signaling components—KRAS, NRAS, JAK2, CBL, and FLT3 [22,28,29]; (4) transcription factors and nucleosome assembly—RUNX1 and SETBP1 [28,30]; (5) tumor suppressor factors—TP53 and PHF6 [31] (Table 1). The gene discussed is TP53; the disease is chronic myelomonocytic leukemia.