Enhanced Upconversion Luminescent Nanocarrier for Effective Tumor‐Targeted Photodynamic Therapy Combined with Immunotherapy

T cell proliferation and suppresses Treg cells, thereby enhancing the antitumor immune response. Furthermore, the synergistic antitumor efficacy of FMUN3-Ce6/IND combining PDT and immunotherapy under in vivo conditions is demonstrated. These results suggest that multi-shell FMUN-based nanocarriers offer a promising platform for synergistic combination therapy, addressing the limitations of monotherapy with IDO inhibitors and overcoming the restricted tissue penetration and low ROS generation associated with conventional PDT.