USD Tether is a Bitfinex issued ERC-20 token which is claimed to be backed by dollar at 1:1 ratio. There are controversial opinions about this and some say it's a scam.
Do you trust USDT or believe it might be a scam?
USDT exists and has been serving us faithfully for a long time. What makes you think this is a scam? Perhaps there were some manipulations, I don't know for sure. But almost all traders outside the market keep their money in USDT.