Triggering receptor expressed on myeloid cells 2 (TREM2) is a glycosylated transmembrane receptor belonging to the immunoglobulin superfamily, predominantly expressed on myeloid cells such as microglia in the central nervous system, osteoclasts, and certain macrophage subsets. It plays a crucial role in immune regulation, mediating anti-inflammatory responses and promoting cell survival, proliferation, and phagocytosis. TREM2 is essential for maintaining tissue homeostasis and responding to damage by activating immune remodeling functions. Its dysregulation is implicated in various diseases, including Alzheimer's disease, where it affects microglial activation and neuroinflammation, and metabolic disorders like obesity and non-alcoholic fatty liver disease. Additionally, TREM2 is a promising therapeutic target in cancer due to its expression in tumor-associated macrophages and its role in modulating the tumor microenvironment.