CD8A and neoplasm: Early syngeneic mouse tumor models demonstrating significant improvements in survival and tumor volume reduction with the combination of RT and PD-1 or PD-L1 blockade compared to single modality and control arms identified elevations in tumor cell PD-L1 expression that were CD8+ T-cell and IFNγ-dependent following irradiation (10 Gy over 5 daily fractions) compared to non-irradiated mice with peak levels occurring 72 h after last dose of RT [86].