Globally, urothelial bladder carcinoma ranks as the tenth most prevalent cancer. Although, on initial diagnosis, merely 5% of cases manifest signs of metastasis, and almost 50% of individuals affected by muscle-invasive bladder cancer (MIBC) and receiving curative-intent therapeutic intervention will ultimately experience recurrence and progression to metastatic disease. MIBC is characterized by genomic instability and a high mutation rate. A consensus classification of six molecular subtypes, based on distinct biological properties, clinical characteristics, and therapeutic targets, will allow identification of predictive biomarkers, influencing drug development and trial design. Notably, specific immune microenvironments are associated with each subtype. The tumor microenvironment (TME) is acknowledged as a pivotal determinant in the various phases of disease advancement, including, but not limited to, local resistance, evasion of the immune system, and the emergence of distant metastases, thereby significantly influencing the prospective evolution of forefront therapeutic approaches in the field of clinical oncology. Cancers can evade immune surveillance through multiple mechanisms, thus enhancing tumor survival, proliferation, and dissemination. Since 1976, non-muscle invasive bladder cancer (NMIBC) has been known to be immune responsive. More recently, immune checkpoint inhibitors (ICIs) have become an important therapeutic approach in advanced/metastatic (a/m) urothelial carcinoma (UC). Immunotherapy has greatly improved patient survival and changed the type of intervention for advanced BC. However, for most patients, any eventual clinical benefit is meager, as the complexity and heterogeneity of the tumor immune microenvironment can inhibit the immune response and reduce the effectiveness of immunotherapy. As yet, no unified standard markers exist for routine clinical practice. The discovery of precise mechanisms related to immune evasion and the development of novel predictive biomarkers could potentially enhance the effectiveness of current cancer immunotherapies. This advancement can be achieved by mitigating tumor-induced immunosuppression, improving host immune response against cancer cells, and facilitating the development of personalized therapeutic strategies in the future.