For patients with HER2-expressing muscle-invasive bladder cancer (MIBC), current neoadjuvant therapies dominated by platinum-based chemotherapy remain unsatisfactory with respect to improved clinical efficacy, pathological complete response (pCR) rates, and the achievement rate of tumor downstaging for bladder preservation; in addition, a subset of patients have limited tolerance or eligibility to chemotherapy. Therefore, this study aims to evaluate the neoadjuvant regimen of Ruikang Trastuzumab combined with Camrelizumab, to determine whether this regimen can, with acceptable safety profiles: elevate pCR rate and the proportion of patients downstaged to ≤T1 disease, enable bladder preservation based on TURBT for eligible patients, and explore predictive biomarkers to identify the population most likely to derive clinical benefits.