LAG-3 immune checkpoint plays an important role in T cell proliferation and activation as a negative regulator of these processes. Along with other inhibitory receptors, LAG-3 helps to keep cytotoxic CD8+ T cells in an exhausted state during highly inflammatory environments such as a chronic viral infection. LAG-3 has also been implicated in memory T cell expansion, Treg function, and the activation and maturation of dendritic cells.