What is the ruling on working in a bank that combines Islamic and commercial transactions?

If the aforementioned bank is usurious in its origin and has established branches for Islamic transactions, we cannot judge them due to not knowing their true nature. However, if the bank is Islamic in its origin, and some prohibited transactions have emerged while the majority of its activities still follow the Islamic methodology, there is no impediment to working there, provided one avoids the prohibited transactions. But if dealing with the prohibited becomes predominant, or if you personally carry out procedures for these prohibited acts, even if minor, then it is not permissible for you to work there.