The goal of this clinical trial is to evaluate the efficacy and safety of neoadjuvant therapy with Sintilimab combined with Disitamab Vedotin in patients with locally advanced, resectable or potentially resectable sebaceous gland carcinoma. The main questions it aims to answer are: What is the major pathological response (MPR) rate after the neoadjuvant therapy? What are the pathological complete response (pCR) rate, clinical objective response rate (ORR), disease control rate (DCR), safety profiles, and 1-year disease-free survival (DFS) of this regimen? Participants will:Receive neoadjuvant therapy consisting of Sintilimab (200 mg, IV, Day 1) and Disitamab Vedotin (2.5 mg/kg, IV, Day 1) every 3 weeks for a total of 2 cycles. Undergo radical surgery after the completion of the neoadjuvant treatment phase. Receive postoperative adjuvant therapy after surgery, which includes uniform Sintilimab monotherapy maintenance (200 mg, IV, Q3W) for up to 1 year, and may receive risk-stratified local interventions (such as local radiotherapy or repeat wide excision) depending on the pathological risk factors.