There are cheats that give you more information than you should have. These typically require access to the game process's memory space.

If you're cheating with a video capture card, this likely means you're allowing a program to rewrite your inputs to more accurately target player models. You will likely be banned if you do this on the same machine via screen capture. A video capture card can process the information on a separate computer, e.g. location of enemies by searching for specific colours, then write into a virtual USB mouse on the gaming rig to keep the player's crosshair on the enemy model. I'm not sure about specifics, but this kind of cheat is almost undetectable; it is only really mitigated by the cost and effort involved to do it.

Players can add additional mitigations on top of this, like only activating aim assist while the shoot button is pressed, to make it entirely undetectable.