CD186, also known as CXCR6, is a G protein-coupled chemokine receptor with seven transmembrane domains. It is expressed on activated and memory T cells and its ligand is the chemokine CXCL16. CXCR6 plays a role in the recruitment of cells to inflamed sites and is also a coreceptor for HIV-1 and SIV to enter target cells, in conjunction with CD4. This receptor is involved in the regulation of T lymphocyte migration to various peripheral tissues and promotes cell-cell interaction with dendritic cells and fibroblastic reticular cells. Additionally, CXCR6/CCL16 controls the localization of resident memory T lymphocytes to different compartments of the lung and maintains airway resident memory T lymphocytes, which are crucial for defense against respiratory pathogens.