If you suspect another member of using disallowed resources you should report them directly to staff.
https://support.chess.com/en/articles/8562517-how-do-i-report-someone
That said discussions of cheating, potential cheating, or cheat detection are not allowed in the general forums.
I am playing at a tournament against a guy who is 1900 ELO, he has played over 120 games in daily chess and has zero loses (not even a GM achieves that).
His moves are extremely sophisticated for a human (specially for a 1900 who is not even close extremely high level).
I have checked some of his games and many of them have over 95% of accuracy (One of them is 99% accuracy and is a long game).
To me, it is very evident what is going on.
If it was some random game I would not care and would just block him, but a tournament is a different thing.
What I have to do so admins check this situation and ban him?