system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How do game anti cheats, like BattlEye or GameGuard work?

What I mean is - I know they can check the processes which are running and are associated to the game that you're playing, but how do they know that those processes are actually cheating tools?
gpt
There are different flags that can be detected to assume someone is trying to tamper the game, such as debugging another process (the game in this case), accessing the memory mapped to that game, running the game in a virtualized environment, tampering the binary or assets and many more. 
Anti-cheat try to detect those abnormal behaviors targeting the game's process.