CD274 and inflammation: Adding to this body of evidence as well as supporting previously published work, we have shown here that (1) IFNAR1 and not PD-L1 signalling is required to prevent CD8+ T cell exhaustion and virus persistence in LCMV-Arm infection, and (2) in the absence of functional IFN-I responses, PD-L1 protects from lethal CD8+ T cell-mediated lung inflammation.