IDO1 and Epstein-Barr virus infection: Some genetic alterations in cellular genes such as indoleamine 2,3-dioxygenase (IDO), PD-L1, cytotoxic T-lymphocyte–associated antigen 4 (CTLA-4), and V-domain immunoglobulin suppressor of T cell activation (VISTA) have been implicated as supporting EBV infection in the lung epithelia [152], and VISTA is a new target for the immunotherapies against cancer [184].