• Patients who have signed an informed consent form and are willing to complete the study according to the protocol;

• Age between 18 and 75 years old;

• Patients with metastatic or unresectable nccRCC who have been histologically or cytologically diagnosed (AJCC 8th edition staging);

• At least one measurable lesion, as required by the Measurable Lesion criteria in RECIST 1.1;

• Not treated with any systemic anti-tumor therapy since diagnosis, including chemotherapy, targeted therapy, and immunotherapy (including but not limited to anti-PD-1/PD-L1 antibodies, anti-CTLA-4 antibodies, etc.);

• Expected survival of 3 months;

• ECOG score 0-1;

• Good organ function: meeting the following requirements:

∙ Absolute neutrophil count (ANC) ≥1.5× 109/L;

‣ Platelet count ≥100×109/L;

‣ Hemoglobin ≥9g/dL;

‣ Serum albumin ≥2.8g/dL;

‣ Total bilirubin ≤1.5 ×ULN, ALT, AST, and/or ALP ≤3 ×ULN; if liver or bone metastasis is present, ALP ≤5 ×ULN;

‣ Serum creatinine ≤1.5×ULN and creatinine clearance rate 60 mL/min (Cockcroft-Gault, see Appendix 3);

‣ Activated partial thromboplastin time (APTT) and international normalized ratio (INR) ≤1.5× ULN (patients receiving stable doses of anticoagulant therapy such as low-molecular-weight heparin or warfarin and whose INR is within the expected therapeutic range of anticoagulants can be screened);

• Patients infected with hepatitis B Virus (HBV) and inactive/asymptomatic carriers, or patients with chronic or active HBV will be allowed to enroll if their HBV DNA\<500 IU/mL (or 2500 copies/mL); HCV antibody-positive patients will be allowed to enroll if HCV-RNA is negative during screening.

• Note: HBsAg-positive patients or patients with detectable HBV DNA who receive antiviral treatment should undergo treatment for \>2 weeks before enrollment, and continue treatment for 6 months after the study drug treatment.

⁃ \*For women of reproductive age, urine or serum pregnancy test results should be negative within 7 days or less before treatment. And use a medically approved contraceptive (such as an intrauterine device, contraceptive or condom) during the study treatment period and at least 3 months after the last use of Serplulimab and at least 6 months after the last use of chemotherapy;

⁃ Male subjects who are not sterilized must be willing to use a medically approved contraceptive method (such as an IUD, contraceptive or condom) for the duration of the study treatment, at least 3 months after the last use of Serplulimab and at least 6 months after the last use of chemotherapy.