With the caveat that there's a lot of space in which users can do things that even kernel level anti-cheat can't detect. Like it can't see what's going on inside plugged in hardware to know if an attached video capture device and the mouse and keyboard is actually all connected to an embedded system that analyses the video stream and adjusts the actual user input to automatically fire if it detects an enemy that would be hit or to nudge the looking direction a bit so that firing would hit.

I've also seen reports of exploits that use the presence of cheat detection combined with other exploits to install cheats on target systems to get their target banned from the game entirely. Which both forces them to deal with a situation they never intended to in the first place (they never tried to cheat), it also gives plausible deniability to actual cheaters who get caught.

One of those cases happened during a live tournament. Dude is playing and all of a sudden can see enemy locations through walls. He knew what was up and left the game to avoid being banned, which makes the tournament itself a bit of a joke.