So basically, a pixel bot will hook into your game and grab your screen (this is why Overwatch applied something called screen-locking but it's bypassed now anyway). It'll scan your screen for certain pixels (normally health bars) and then draw a hitbox where it then aims inside of. Memory cheats are detecting the values of players (normally a dynamic EntityList) and then setting your mouse to aim at that value, Pixel bots will tend to go undetected for much longer due to not interacting with the game as much.