CD8A and Epstein-Barr virus infection: ICI starting 3 wpi applied a total of 7× until 5 wpi/Anti-PD-1 mAb (clone EH12.2H7 Biolegend) 100–150 μg per administration/7× administrations/Control: PBS or 150 μg of isotype control antibodyICI applied during in vivo T cell priming resulted in elevated viral load (blood P < 0.05, spleen P < 0.001), elevated tumor burden (P < 0.05./CD3 T cell numbers in blood not changed/Lower frequencies of PD-1+ CD8 T cells (P < 0.0001)/Elevated levels of cytokines (IFN-γ, TNF-α, IL-10, IL-8 P < 0.05 to P < 0.001)Function of PD-1 axis necessary for control of EBV infection and tumorigenesis