I always get asked to repair cracks in concrete driveways, after all its what I do. Most cracks occur in concrete from movement underneath the slab. The crack occurs at the stress point in the slab. Concrete is so hard that it really has no flexibility to it so it has to give way by breaking.
The time comes to repair and should be done before old man winter makes it worse. Water can get into the crack, freeze and break the concrete away exposing more problems. The crack will need to be chased then bonded with repair material that is stronger than concrete. If the slab is still moving this can be a problem down the road as the concrete can break again. Slab jacking can help bring the slab level again and remove some of the stress so the repair can have better success. Once bonded the crack can then be filled with concrete.
Once you fix the crack and it is filled you still have an ugly crack. You can then coat with protective coating to hide all the repairs and make your driveway look new again!