Endostar Plus Toripalimab as Adjuvant Therapy for Resectable Stage III-Oligometastatic Stage IV Cutaneous Melanoma

The goal of this clinical trial is to evaluate the efficacy and safety of Endostar combined with Toripalimab in the adjuvant treatment of resectable stage III-oligometastatic stage IV melanoma, and to find effective biomarkers of efficacy based on tumor paraffin tissue specimens and peripheral blood. The main questions it aims to answer are: * The efficacy and safety of the combination treatment regimen; * Finding suitable biomarkers can refine the patients with effective treatment After a series of evaluation, if the participants meet the inclusion and exclusion criteria and are evaluated by the investigator, they will formally enter the study observation period and receive the following treatments Endostar: The dose of 210 mg (14 vials) is administered by intravenous pump from Day 1 to Day 3 of each course, every 4 weeks as a cycle, until disease recurrence, metastasis or intolerable toxicity, and up to 6 courses of administration. Toripalimab: 3 mg/kg by intravenous drip every 2 weeks (Day 1 and Day 15 of each cycle) in a 4-week cycle until disease recurrence, metastasis, or intolerable toxicity for up to 1 year (about 13 cycles).