What Aim Assist ?

Played some modern warfare this evening. Went into shipment for a bit. Remembered I've been seeing videos lately of aim assist demonstrations. So I tried a few things to see it in action. Im on pc with controller btw. I tried each setting with and without aiming down. Standard, Precision, and Focusing. I set my crosshairs to where someone would come across them and I shit you not my crosshairs do not move in any scenario. So I dont know if there's another setting im missing or what but I get nothing. Ive had mine on Standard for as long as I can remember. I can upload some clips if needed but I've only actually noticed AA in Cold War.. nothing else.