[Semaphor]

Those have been common for decades and are pretty much the lowest bar for detection.

[socialismisok]

Using computer vision on the video stream (eg via a capture card) and then sending valid mouse and keyboard inputs most definitely has not been around for decades. It's a mechanism to cheat that has zero binaries running on the host computer.

[eru]

You could do statistical analysis on the mouse and keyboard inputs to try and detect this.

(Very similar to how you might detect chess cheaters, actually.)

[erwincoumans]

You can use (the data of) statistical analysis to train a deep neural network to avoid detection. That may also help avoiding chess detection cheaters, so the moves are not perfect anymore.

[eru]

Yes. You can't make cheating impossible, but you can make it harder to pull off.