PRF1 and neoplasm: The effectiveness of immune checkpoint blockade (ICB) therapy stems from the rejuvenation of CD8+ T cells, which detect tumor antigens presented by MHC-I molecules on tumor cells through a peptide-specific mechanism.76 Interferon (IFN) can enhance antigen presentation and MHC expression.77 Upon recognizing antigens, CD8+ T cells secrete perforins, granzymes, and IFN-γ, leading to the death of tumor cells.78 The significant infiltration of CD8+ T lymphocytes serves as an indicator of an immune response within “hot” tumors.