Pharmacodynamic effects of oncolytic viruses in the tumor microenvironment, including increased interferon production, CD8+ T cells, and programmed death ligand 1 (PD-L1) expression [9] and reduced suppressor T-cell populations [10], suggest the potential for improved responses when combined with immune checkpoint inhibitors such as those targeting programmed death 1 (PD-1)/PD-L1 or cytotoxic T-lymphocyte antigen 4 (CTLA-4). The gene discussed is CD8A; the disease is neoplasm.