Theres two main options, short of running new outlets
You can hide the cables with a plastic tubing(and then most people would paint the tube the same color as their wall to make it blend in. like this:
Or, there are kits you can buy that require you to cut a small hole in your drywall behind the TV, and then another down at the bottom of the wall, and then you feed the cords down through the wall to the bottom where they can plug in to your existing outlet & cable/satellite box. Home depot/Lowes sells kits to do this which come with little plastic facings to cover the holes and make them look nice.
They can be complex like the ones pictured, or I've also seen ones that are simply nothing more than a 2-inch wide round circle hole for the cables