In recent years, several clinical trials focused on the potential role of immune-checkpoint inhibitors (ICIs) in the adjuvant treatment of muscle-invasive urothelial cancer (UC). Heretofore, only the anti-programmed death protein 1 (anti-PD1) nivolumab received European Medical Agency (EMA) approval for cisplatin-unfit patients. In our work, we deeply analyzed the results of the three pivotal studies in view of the rapidly evolving therapeutic advanced UC's scenario. Furthermore, there are several ongoing research to investigate ICIs and other emerging immune agents in this setting; results are awaited. Additionally, current efforts have been made to assess the role of these agents in earlier disease settings, particularly in high-risk non-muscle-invasive bladder cancer (NMIBC). In our review, we analyzed the potential role of predictive and/or prognostic biomarkers that may improve patient selection and treatment efficacy. To conclude, we highlighted the upcoming changes that could redefine the standard of care for patients with early-stage UC.