Let me clarify @oldturkey03's answer if I may.
The brake booster is basically what gives you power brakes. Although we take it for granted nowadays, cars did not always come with power brakes. Those that didn't required significant effort in pushing the brake pedal to get the car to stop. The addition of a brake booster uses a vacuum motor to amplify your foot press and make it easier to push the pedal hard enough to stop the car.
So now we have power brakes, and almost all of them work off of the vacuum generated by the air flowing inside the intake manifold. However, some newer vehicles like yours do not generate enough vacuum to run a brake booster. When that's the case, rather than redesign the brake booster to run off some other form of power, they add a vacuum pump to create enough vacuum for the old school style of brake booster.
So there's where you get the two separate things. Other cars only have a brake booster, but yours has a vacuum pump and a brake booster, and both are required for you to have power brakes.