What is the ruling on working in a European bank in a department far from usurious activities, where a company for IT services lends the employee to the bank for a daily wage?

It is not permissible to provide services to usurious banks in any way, as it involves assisting in forbidden transactions, due to the Almighty's saying: "And cooperate in righteousness and piety, but do not cooperate in sin and aggression." So, if you know that your services will be provided to the usurious bank to assist it in its forbidden activities, then it is not permissible to work for that institution. However, if the services could potentially be provided to banks or to others, then there is no harm in working.