I was hoping to get a response back from you before answering. The first thing I would check would be his health. Dogs will often seek a place away from their family (pack) when they are not feeling well. So the first thing would be to get a health check done.
The second thing would be to retrain him to the recall (come) command. Many dogs don't come when called because they have learned that the only time they are called is when fun time is over. People call their dogs to them to make them come inside or to stop chasing prey (cats) or to be put on leash (end of free running time) or even crated. The only association they have with the come command is negative.
Additionally, dogs find chase to be a highly amusing game and have learned that if they get close to a human, the human might chase them. They love a good game. So what you need to do is make coming to you more pleasurable.
The easiest way is to reward your dog with small tiny treats and praise whenever your dog comes to you when you give the command. Do this even when the dog wants to come to you. After a few treats, the dog will associate coming to you with getting treats and praise. Outside, you will want to use a long lead. Do not drag your dog to you, but say the command and if the dog doesn't come, give the leash a short tug. Start with short distances and gradually extend the distance as your dog becomes more familiar with the command. Over time, you will reduce the treats and increase the praise until praise is the only reward. Another thing to remember is to never call a dog to you to discipline it, go to the dog. During training I don't call a dog to me unless it is going to be pleasant for the dog. I usually don't have much of a problem since the dogs quickly learn that I have thinly sliced hot dog treats just waiting for them to obey me.
Now it is likely to be a health issue if he used to come inside all the time, so get that checked first, but the above techniques seems to still work to retrain a dog as well.
I hope this information is helpful to you. If you would like any additional information or have more questions please don’t hesitate to press the reply to expert or continue conversation button so I can address any issues you still have . If you do find this helpful, please take this opportunity to rate my answer.