Dipeptidyl peptidase IV (DPPIV), also known as adenosine deaminase complex protein 2 or CD26, is an antigenic enzyme expressed on the surface of most cell types, associated with immune regulation, signal transduction, and cell apoptosis. It is a congenital membrane glycoprotein and serine exopeptidase. DPPIV plays an important role in glucose metabolism, responsible for the degradation of intestinal proinsulin such as GLP-1. In addition, it can also inhibit the development of cancer and tumors. Animal experiments have shown that it plays a pathogenic role in the development of fibrosis in many organs such as the liver and kidneys. DPPIV plays an important role in tumor biology and is an effective biomarker for various cancers. Its levels increase on the cell surface or serum of some tumors and decrease in other tumors. Middle East Respiratory Syndrome Coronavirus, a new coronavirus associated with SARS, has been found to bind to DPPIV. DPPIV exists on the surface of cells in the airways (such as lungs) and kidneys, and scientists use their advantage to block virus entry into cells.