In bladder cancer, the clinical and histopathological features are just part of the oncological issue with an extremely complex and large underlying molecular biology. Fibroblast growth factor receptor 3 was identified in the low-grade and/or pTa pathway; it was found that tumors in the carcinoma in situ and high-grade pathway mostly developed as a result of the inactivation of tumor suppressor genes such as TP53 and retinoblastoma gene. There are many molecular classifications in bladder cancer, but it was accepted that there may be different subgroups specific to the studies, mainly divided into two subtypes “basal” and “luminal.” The basic areas of use and goal of molecular classification are evaluating the prognosis, predicting the response to neoadjuvant chemotherapy, predicting the response to immune checkpoint inhibitors, determining changes in the treatment approach, and determining the group that requires early radical cystectomy. Over the past 20 years, a number of therapeutic advancements for muscle-invasive bladder cancer (MIBC) have been made, but clinical implications have not yet changed significantly. Information obtained from comprehensive genetic studies in bladder cancer may be of significant use in diagnosis, therapeutic decision-making, and predicting prognosis. Molecular subtype–specific therapeutic strategies are important, and individualized treatment is an important step for the future in determining the right treatment for the right patient.