When conducting due diligence for a foreign correspondent bank account, a bank typically needs to know the identities of the correspondent bank's true ownership, information on government licenses, and information on the products and services offered to assess risk and compliance. However, copies of the tax return of the correspondent bank are not generally required for this process. Tax returns are more relevant for detailed financial assessments or specific legal and tax-related inquiries rather than standard due diligence for correspondent banking relationships.