Inclusion Criteria:
* Patients included in this study must meet all of the following criteria:
1. Aged 18 or above;
2. Histologically or cytologically confirmed locally advanced inoperable (such as T4b, or N2-3) or metastatic urothelial carcinoma, including bladder, ureter, renal pelvis and urethra;
3. Patients who have received previous treatment with immune checkpoint inhibitors (PD-1/PD-L1 monoclonal antibodies) are allowed;
4. According to RECIST1.1 standard, there is at least one measurable target lesion;
5. ECOG score ≤2;
6. Good bone marrow, kidney (serum creatinine clearance calculated by CG formula\> 30 mL/min), liver and coagulation function:
7. Expected survival period ≥ 6 months;
8. The patient understands the research procedures and signs the informed consent form in writing to indicate his/her agreement to participate in the study;
9. Female subjects of childbearing potential should have a negative urine or serum pregnancy test within 7 days before the first dose of study drug (Cycle 1, Day 1). If the urine pregnancy test result cannot be confirmed as negative, a blood pregnancy test is required.
10. If there is a risk of pregnancy, male and female patients should use highly effective contraception (i.e., a method with a failure rate of less than 1% per year) and continue for at least 180 days after stopping the trial treatment.
Exclusion Criteria:
* Any of the following will be considered as meeting the exclusion criteria of the study:
1. Patients with locally advanced disease may receive local radical treatment;
2. History of clinically symptomatic cardiovascular, liver, respiratory, renal, hematoendocrine, or neuropsychiatric diseases;
3. Clear brain/meningeal metastasis;
4. Peripheral neuropathy \>1 degree;
5. Patients who have received anti-tumor monoclonal antibody treatment within 4 weeks before the start of the study, or have received other anti-tumor drug treatment and have not recovered from adverse events/reactions;
6. Participated in any investigational drug treatment within 4 weeks before the start of treatment;
7. Patients who had received axial bone radiotherapy within 4 weeks before the start of the study or had not recovered from adverse reactions caused by previous radiotherapy;
8. Known severe allergic reaction to the study drug, its active ingredients and/or any excipients;
9. Patients diagnosed with immunodeficiency or receiving systemic glucocorticoids or any other form of immunosuppressive therapy within 7 days before the first dose of the study; physiological doses of glucocorticoids (≤10 mg/day of prednisone or equivalent drugs) are allowed;
10. Active autoimmune diseases requiring systemic treatment (such as the use of disease-modifying drugs, corticosteroids, or immunosuppressants) occurred within 2 years before the first dose. Replacement therapies (such as thyroxine, insulin, or physiological corticosteroids for adrenal or pituitary insufficiency) are not considered systemic treatment; a history of non-infectious pneumonia requiring glucocorticoid treatment within 1 year before the first dose or current interstitial lung disease;
11. Received solid organ or blood system transplantation;
12. Known history of human immunodeficiency virus (HIV) infection (i.e. HIV 1/2 antibody positive). Untreated active hepatitis B;
13. Untreated active hepatitis B; Note: Hepatitis B subjects who meet the following criteria are also eligible for inclusion: HBV viral load must be \<1000 copies/ml (200 IU/ml) before the first dose, and subjects should receive anti-HBV treatment during the entire study chemotherapy treatment to avoid viral reactivation. For subjects with anti-HBc (+), HBsAg (-), anti-HBs (-), and HBV viral load (-), preventive anti-HBV treatment is not required, but viral reactivation needs to be closely monitored;
14. Subjects with active HCV infection (HCV antibody positive and HCV-RNA level above the detection limit) received live vaccine within 30 days before the first dose (Cycle 1, Day 1);
15. A history of other malignant tumors in the past 5 years, excluding cured non-malignant melanoma of the skin, cervical carcinoma in situ, and incidentally discovered prostate cancer (stage lower than T2N0M0, Gleason score \<7, or undetectable PSA);
16. Medical history or disease evidence, abnormal treatment or laboratory test values, or other conditions that the researcher considers unsuitable for enrollment that may interfere with the trial results or prevent the subject from fully participating in the study;
17. Breastfeeding women
18. People with chronic diseases who need to take antibiotics for a long time.
