An isolated Usp22 knockout in CD8+ T cells might rescue the mice from immunopathology and liver damage after acute LCMV infection because the Usp22 expression is not impaired in the antigen-presenting cells and, consequently, these cells would display regular PD-L1 expression, stopping the exaggerated T activation of CD8+ T cells during virus infection. Here, USP22 is linked to viral infectious disease.