chess.com takes cheating very seriously from what I can see. They have some sophisticated methods for detecting cheaters. And I have seen many account closed down over the last few years for cheating.
But don't worry about it. Play your own game, enjoy your chess, and let chess.com worry about the cheaters.
What does chess.com do about cheaters? There are players on here who play perfect chess and have never lost. I've reported one player but did not hear back. It's ridiculous that players cheat in the first place. It's some ego thing where they actually feel good about winning by cheating, but it ruins it for people who are actually putting the work in to improve their chess. I read some where a while ago that chess.com is great a catching cheaters, but it sure doesn't seem like that to me.