Melanoma has emerged as the fastest-growing malignancy in recent years, with incidence and mortality rates among both men and women in East Asian countries exceeding the Asian average. China ranks fifth among East Asian nations in melanoma incidence. Currently, immune checkpoint inhibitors are achieving significant breakthroughs in adjuvant melanoma therapy. This study aims to evaluate the efficacy and safety of sintilimab combined with chemotherapy versus chemotherapy alone in patients with PD-L1-positive, completely resectable mucosal melanoma, thereby providing additional clinical evidence for treatment decisions.