CD197, also known as CCR7, is a seven-transmembrane, G-protein-coupled receptor that plays a crucial role in the immune system. It is expressed on activated T cells, B cells, and dendritic cells, and is involved in lymphocyte migration to lymph nodes and the maturation of dendritic cells. CD197 binds to chemokines such as CCL19 and CCL21, which are essential for the interaction between T cells and dendritic cells, thereby linking innate and adaptive immunity. Additionally, its expression is significantly upregulated in B cells infected by the Epstein-Barr virus.