Toll-like receptor modulators are primarily used in immunotherapy to enhance or suppress the immune response. They are applied in the treatment of various diseases, including cancer, infectious diseases, and autoimmune disorders. By targeting specific Toll-like receptors, these modulators can activate innate immunity, promoting the body's defense mechanisms against pathogens. In cancer therapy, they are used to stimulate the immune system to recognize and attack tumor cells. Additionally, they play a role in vaccine development, improving the efficacy of vaccines by boosting the immune response. In autoimmune diseases, certain modulators can help reduce inflammation by dampening overactive immune responses. Research is ongoing to explore their potential in treating chronic infections and inflammatory conditions.