GZMB and neoplasm: Within theimmunosuppressive TME, cold tumor cells display restrictedPD-L1 expression on their surfaces and lack T cell infiltration, leadingto poor responses to ICI treatments.8,9 Conversely,within the immune-active TME, hot tumor cells demonstrate heightenedsurface PD-L1 expression and are accompanied by abundant T cell infiltration.8 Once activated, these T cells can secrete elevatedlevels of granzyme B (GrB) and proinflammatory cytokines, includinginterferon γ (IFN-γ), interleukin-2 (IL-2), and tumornecrosis factor α (TNF-α).