PDCD1 and glioma: Another study has demonstrated how a single i.v. infusion of reovirus in a small cohort of patients with recurrent high-grade gliomas, 3–17 days before surgery, increased cytotoxic T cell tumor infiltration, upregulated IFN gene expression, and increased the PD-1/PD-L1 axis in tumors via an IFN-mediated mechanism, all of which were shown to potentially enhance the sensitivity of glioma cells to ICI treatment.