<i>In vitro</i>, AGEs did not alter OSCC cell viability but suppressed CD8+ T cell production of IFN-γ and GZMB, increased oxidative stress, and reduced tumor cell susceptibility to T-cell cytotoxicity (all P<0.05).<h4>Conclusion</h4>This study provides genetic and experimental evidence for a protective, immune-mediated role of HbA1c in oral cavity cancer. Here, GZMB is linked to oral cavity cancer.