Unexpected USDT deposit

I received an unexpected deposit of around $1k USDT. I am aware this can many times be related to a scam... but im not sure how.

It is official USDT deposited to my Coinbase acct. I have no other assets in the acct right now. nobody has asked for it back or anything....

I would appreciate any advice. could I leave it a while and use it eventually if nothing happens? do I send it back? im not really sure what to do about it. very strange.

im adding more here as I need 500 characters but thats the long and short of it.