GM-CSF (Granulocyte-Macrophage Colony-Stimulating Factor) is a multifunctional cytokine belonging to the interleukin family. It is a glycoprotein composed of a single-chain peptide. GM-CSF is primarily produced by immune cells such as T cells, macrophages, and endothelial cells, and is widely distributed in various tissues and organs in the body. GM-CSF is involved in regulating hematopoiesis, immune responses, and inflammatory reactions. By binding to its specific receptors, GM-CSF activates signaling pathways such as JAK/STAT, PI3K/Akt, and MAPK, promoting proliferation, differentiation, and activation of bone marrow cells. The gene expression of GM-CSF is tissue-specific, and its overexpression or dysregulation is associated with the occurrence and development of various inflammatory and autoimmune diseases.