Probiotics Combined With Targeted Therapy Plus Immunotherapy in Bladder-Preserving Setting for Patients With MIBC

The goal of this clinical trial is to learn if oral probiotics (Clostridium butyricum) work to improve the efficacy of targeted therapy plus immunotherapy in bladder preservation setting for cisplatin-ineligible T2-3N0M0 bladder cancer patients with low serum butyrate. The main questions it aims to answer are: Do oral probiotics elevate serum butyrate levels and enhance the duation of bladder preservation interval with targeted therapy plus immunotherapy? Researchers will compare oral probiotics combined with targeted therapy plus immunotherapy to standard regimens (targeted therapy plus immunotherapy) to see if oral probiotics can improve its efficacy. Participants will: 1. Take oral probiotics and/or Disitamab Vedotin (HER2-ADC) and Toripalimab (PD-L1 inhibitor) for one year in total, which is divided into induction treatment period, intensive treatment period and maintenance treatment period. 2. Return to the hospital for evaluation of tumor residual burden according to the follow-up plan, which will include urine cytology, imaging, surgical biopsy, and urine DNA methylation detection.