I often receive spam messages of the form of an individual who claims some position of relative ignorance (e.g. being a student) and to have received some moderately large sum of money on-chain but not knowing how to get government-issued funds into their bank account. The message includes a 12-word mnemonic seed phrase and private key corresponding to an empty/never-used account; if it did have any remaining value I as a stranger to the message sender would be able to irreversibly take it (the context is one where the sender doesn't know much about my trustworthiness). My non-response means it doesn't go further, but how is this scam supposed to work?
The funds in the scam wallet are generally stable coins like USDT/ BUSD or the likes of it. To actually do anything on chain, you need the chain coin like ETH or BNB. The scammer scans the wallet all the time and once you transfer ETH or BNB for the said actions on the chain. He will transfer your ETH or BNB out.
Other stuff is what is mentioned in the previous answer by Pandapip1.