PF-4989216 is a selective inhibitor of Smoothened (SMO) in the Hedgehog signaling pathway. It is primarily investigated for its potential in cancer therapy, particularly for hedgehog pathway-dependent tumors such as basal cell carcinoma. It functions by disrupting signaling mechanisms that promote tumor growth and cancer cell survival and proliferation. Research focuses on its efficacy, safety, and potential integration into combination therapies for treating various malignancies. Studies are ongoing to evaluate its therapeutic applications.