If you are seeing USER_SETUP_REQUIRED on a US Bank Item, first check the common causes and troubleshooting steps for that error. The most common reasons are that the user needs to accept new Terms and Conditions with their institution, reset a password, or some other step that they need to take before they can connect their account. From there, you can prompt the user to re-authenticate via Plaid Link.
For US Bank there is an additional common cause. Users have to wait 72 hours after creating an account before they are able to connect it to a third-party data provider. So if a user has just opened an account they will just need to wait 72 hours before connecting through Plaid.