In contrast, PD-1/PD-L1 blockade during chronic viral infections restores the function of exhausted CD8+ T cells, in particular antigen-specific cells, and results in enhanced T cell responses and virus control in different virus models8,52,53, which suggests that these two molecules operate through distinct pathways to dampen immune cell responses and might thus partake in different physiological processes, where immune suppression is required. The gene discussed is CD8A; the disease is viral infectious disease.