So far it seems to be a Telegram channel dedicated to some sort of card counting, which is not necessarily an attempt to scam anyone at a first glance.
Though, It would be silly to assume cars counting could give one an advantage against the house when comes to blackjack, it is common knowledge casinos use multiple decks of cards in live casinos in order to deter those who count cards to increase their leverage against the house.

Probably there is some scam behind all of this, but I would not give deeper. I prefer just to be cautious, there are a lot of scams in Telegram, that is for sure.