If your client is an individual, there's no information return that needs to be filed for the inbound transfer (although the bank may have to do some filing).  However, your client will likely have other filing requirements.

If it's coming from a bank account your client maintains overseas, your client will have at least a filing requirement for FinCEN 114 but may also have a filing requirement for F.8938 (FATCA), depending on the filing status, whether your client resides in the US, and the aggregate maximum value of the SFFA.

In case the money is coming from a foreign trust or bequest, your client will need to file F.3520.