To Explore the Efficacy and Safety of SHR-1701 Combined With Temozolomide in the Treatment of Advanced Melanoma

Inclusion Criteria:

* Has unresectable Stage III or Stage IV or melanoma per American Joint Committee on Cancer (AJCC) staging system version 8. At least one measurable lesion conforming to RECIST 1.1 criteria.
* No previously received systematic therapy.
* The toxicity of prior treatment has recovered to ≤1 grade according to CTCAE 5.0.
* ECOG score 0-1.
* The expected survival time is ≥ 12 weeks.
* Adequate organ and bone marrow function.
* Female subjects of childbearing age must undergo a serum pregnancy test within 7 days before the commencement of the study and the results are negative, and are willing to use a medically approved high potency contraceptive method during the study period and within 3 months after the last administration of the study drug; For male subjects whose partner is a female of childbearing age, they should be surgically sterilized or agree to use an effective method of contraception during the study period and for 3 months after administration of the last study.
* Willing to consent and signed the informed consent, and able comply with the planned visit, research treatment, laboratory examination and other test procedures.

Exclusion Criteria:

* History of other malignant tumors, except for cured skin basal cell carcinoma, squamous cell carcinoma of skin, superficial bladder carcinoma, papillary thyroid carcinoma, intraductal carcinoma and cervical carcinoma in situ.
* Has ocular melanoma.
* The first study drug treatment was less than 4 weeks from the last systematic antitumor therapy or 5 half-lives from the last targeted therapy; less than 4 weeks from major surgery; less than7 days from immunosuppressive drug; less than 3 weeks from immunomodulatory; less than 4 weeks from live attenuated vaccine.
* Systemic antibiotic use for 7 days within 4 weeks prior to initial administration, or unexplained fever during screening/prior to initial administration.
* With active autoimmune disease or a history of autoimmune disease.
* With history of allogeneic organ transplantation or allogeneic hematopoietic stem cell transplantation.
* With immunodeficiency, eg HIV, HBV, HCV.
* Have a clear history of serious and uncontrolled other disease or mental disorders.
* Has a bleeding tendency or abnormal clotting function.
* Subjects with central nervous system disease or brain metastases.
* Known to be allergic to the active ingredients or excipients in this study.
* Other situations that the researcher considers inappropriate to participate in the research.