CC-99677 is a selective allosteric inhibitor of TYK2 (tyrosine kinase 2), primarily investigated for its therapeutic potential in autoimmune and inflammatory diseases. It targets dysregulated immune signaling pathways, showing promise in preclinical and early clinical studies for conditions such as rheumatoid arthritis, psoriasis, and inflammatory bowel disease. By modulating cytokine signaling, CC-99677 may reduce inflammation and autoimmune responses with a potentially improved safety profile compared to pan-JAK inhibitors. Preliminary research also explores its role in oncology, where it could inhibit cancer cell proliferation in certain tumors driven by similar pathways. The compound remains in experimental stages, with ongoing trials evaluating its efficacy, safety, pharmacokinetics, and potential synergies with other therapies.