Many of the telegram groups which give signals are run by the same people, I have noticed on multiple occasions of the groups giving the same signals. Many of the groups also conduct coordinated pump and dumps, and they usually send it in all the groups to gather a greater audience. Although some of the signals turn out to be correct, always do your own research before making a trade.
It is really good to see the signal if trades for yourself other than basing your decisions to others. Telegram groups which give signals on trade usually receives money or being paid by some admins to promote their coins. So it would be best to trust only your intuition in deciding when and what to trade.