CD274 and neoplasm: XA5508 utilized anti-PD-L1 Nb to recognize and bind to PD-L1 on the surface of tumor cells, sustainably delivered cGAMP into liver cancer cells, effectively and selectively activated the STING pathway in tumor cells, thereby enhancing the biological activity of cGAMP, stimulated the interferon response, and simultaneously reduced the immunosuppressive cell population in the TME, such as M2-type macrophages.