Sichuan Kelun-Biotech Biopharmaceutical Co. Ltd. has described Toll-like receptor 7 (TLR7) and/or TLR8 agonists and their immunostimulatory antibody conjugates (ISACs) consisting of antibodies covalently linked to TLR7 and/or TLR8 agonists through cleavable or uncleavable linkers.