Come is most often used without teaching the dog what it means first, so it just becomes a meaningless word. Teach your dog to come on a lead when it's a puppy.
Many people call their dog back, ask them to sit and give them a reward. This rewards them to sit not to come. Don't ask them to sit. Just reward them.
Make coming back to you exciting! The world is full of wonderful things to see and smell, you need to be better than the rest of the world. Be exciting.
Don't always call your dog for boring and of fun things. Ask them to come and then let them run free again. Call them to you to play a game..