HLX316 (E-688) is an engineered human sialidase fusion protein that targets B7-H3 (CD276). HLX316 removes immunosuppressive sialoglycans from the tumor surface through enzymatic cleavage, thereby neutralizing Siglec-mediated immune evasion. HLX316 also specifically binds to B7-H3 on the surface of tumor cells, enabling precise tumor enrichment. HLX316 is suitable for use in studies of advanced solid tumors.