Camber is the angle that measures the tilt of the wheel. A wheel that is tilted outward has a positive camber reading, and a wheel that is tilted inward has a negative camber reading. All readings are measured in degrees.
Camber is a live angle. A live angle is one that is updated on the alignment screen in real time and it also means they are tire wearing angles. An out of adjustment camber issue can also cause a "pull" to the side with the most positive camber.
In most vehicles, camber is not a factory adjustable angle on the rear or the front. Generally, aftermarket kits are available to allow adjustment of the strut via camber bolts that hold the strut to the spindle. The only reasons that camber can become maladjusted are: a wreck or potholes that result in bent suspension parts, aftermarket modifications such as lower springs or air ride, or failing suspension parts like broken springs and loose ball joints. Camber adjustment directly effects the adjustment of the angle Toe.
So in review, maladjusted camber can cause uneven tire wear, alignment pull, and must be adjusted before toe.