For someone who's not the biggest baseball fan, what happened with the Houston Astros and how did they cheat?
They used a camera in center field to read the signs the catchers were giving the pitcher about which pitch to throw next, then signaling their batter to know what pitch to expect.
It's kinda expected that teams will steal signs when they can, but the league has been more and more strict about declaring that they aren't allowed to use technology to steal signs and aren't allowed to use technology to communicate information to players during the game. The MLB had been extremely clear about that and started fining teams and shyt and the Astros went ahead and blatantly violated the rules anyway.