CD274 and neoplasm: Interestingly, when tumors were assessed by IHC, it was found that mice therapeutically treated with any vaccine containing CPIs (anti-PD-1, anti-CTLA-4 and anti-PD-L1) harbored tumors that were largely non-viable compared to control mice or mice treated with SLA–OVA (adm) alone where the tumor tissue was mostly viable.