Sintilimab Combined With Chemotherapy for Adjuvant Treatment of Mucosal Melanoma After Surgery

This study is testing whether adding sintilimab — an immunotherapy drug that helps the immune system fight cancer — to chemotherapy as an adjuvant (post-surgery) treatment can prevent mucosal melanoma from coming back. Mucosal melanoma is a rare and aggressive cancer that arises in mucous membranes (such as the mouth, sinuses, or digestive tract), and it has fewer treatment options than skin melanoma. **You may be eligible if...** - You are 18 or older - You have confirmed mucosal melanoma that was completely surgically removed (negative margins) - Your tumor is PD-L1 positive (a marker showing the immune system may respond to immunotherapy) - You have not received any prior immunotherapy, interferon, or chemotherapy for this cancer - Your cancer has not come back based on recent imaging **You may NOT be eligible if...** - You have previously taken any anti-PD-1 or anti-PD-L1 immunotherapy drug - You have active autoimmune disease requiring treatment - You have active hepatitis B, C, HIV, or tuberculosis - You have serious heart conditions or uncontrolled high blood pressure - You are pregnant or breastfeeding Talk to your doctor to see if this trial is right for you.