Usually, melanoma of the left thumb, usually can be treated by surgical treatment, biological treatment and other ways. Patients with stage I-II melanoma are recommended to have surgical resection of primary foci, or patients with ulcers are recommended to have sentinel lymph node biopsy, stage III patients are recommended to have regional lymph node dissection in addition to surgical resection of primary foci, and surgical treatment is also recommended for patients with isolated metastasis in stage IV. For patients with advanced malignant melanoma, biological treatments such as interleukin, interferon and other cytokines can be used. For patients who cannot tolerate surgery, chemotherapy is feasible. For patients with cutaneous melanoma, the earlier it is detected, the greater the likelihood of cure and the better the prognosis. For high-risk groups, regular screening is done and sun protection is usually done.