No matter what roads you drive on, whether they be country back roads or highway interstates, are probably designed with a few degrees of camber. That means instead of being completely flat, there's a bit of a crown to the road's shape, meaning its higher in the middle than on either side. Depending on how much camber a road has, it could have a drastic effect on how much grip you have when, say, you go into a corner.
Wyatt Knox of the put together a video explaining how camber can affect what kind of line you should take through a corner, and how to use it to your advantage. If, for instance, you're approaching a corner on a rally stage, logic dictates you should approach it and exit from as far outside as possible, apexing in the middle for the straightest line. But if that road is heavily cambered, using the outside of the road may actually suck you away rom the apex, since the road is sloped opposite of where you want to go. In that case, it would be better to stick inside and ride the camber facing inward.
It makes more sense once you see Knox actually demonstrate it in person with a car. Check out the full video right here.