Yeah its a scam dont fall for it. Both etn and etcv asking for private keys to be able to get the airdrop. You have been warned.
I don't think ETCV is asking for Private keys. You just have to hold them in your wallet.
You can read and research regarding these coins. Both etn and etcv codes were shown here.
https://bitcointalk.org/index.php?topic=5079183.0 you can see that both were asking for private keys