CFU-GM (or "GMP", for "granulocyte-macrophage progenitor") is a colony forming unit. It is derived from CFU-GEMM.
The "GM" stands for "granulocyte, monocyte".
It is the precursor for monoblasts and myeloblasts.
Production is stimulated by granulocyte macrophage colony-stimulating factor (GM-CSF).
There is some controversy over which granulocytes derive from CFU-GM.