MIF (Macrophage Migration Inhibitory Factor) is a multifunctional cytokine belonging to the MIF family, which includes MIF and D-DT (MIF-2). MIF is a trimeric structure composed of three identical subunits and is widely distributed in various cells and tissues, such as immune cells, endothelial cells, and epithelial cells. MIF is involved in regulating immune responses, inflammation, and cell proliferation. By binding to its receptor CD74, MIF activates downstream signaling pathways such as MAPK, PI3K/Akt, and JAK/STAT, affecting the production of cytokines and cell activity. The expression of MIF is tissue-specific, and mutations or dysregulation in its gene expression are associated with the occurrence and development of various diseases, including autoimmune diseases, infectious diseases, and tumors.