Cancer immunotherapy has emerged as a potent treatment strategy by harnessing the host immune system to target cancer cells. However, challenges including low tumor vaccine immunogenicity and tumor heterogeneity hinder its clinical efficacy. To address these issues, we propose a novel nanoplatform integrating photothermal material gold nanorods (GNRs) with polyphenols for enhanced immunotherapy efficacy via photothermal therapy. Polyphenols, natural compounds with phenolic hydroxyl groups, are known for their ability to bind tightly to various molecules, making them ideal for antigen capture. We synthesized GNRs modified with polyphenols (GNR-PA and GNR-GA) and demonstrated their ability to induce immunogenic cell death upon laser irradiation, releasing tumor-associated antigens (TAAs). The surface polyphenols on GNRs effectively captured released TAAs to shield them from clearance. In vivo studies confirmed increased accumulation of GNR-GA in lymph nodes and enhanced dendritic cell maturation, leading to promoted effector T cell infiltration into tumors. Furthermore, treatment combined with PD-1/PD-L1 pathway blockade demonstrated potent tumor regression and systemic immunotherapy efficacy. Our findings highlight the potential of this photothermal nanoplatform as a promising strategy to overcome the limitations of current cancer immunotherapy approaches and improve therapeutic outcomes.