Dog Collars With Name Tag

What do I do when i find a lost dog?
I took my dog for a walk and this lost dog with a collar but no name tag comes up 2 us. It keeps its distance and look for its owner.But no luck. So we continue our walk. But it keeps following us. it even follws me 2 my house. Its just sitting in my back yard staring at me. What should i do?
Call animal control. It’s owner is probably looking for him and they will keep him healthy and safe in the meantime.
Lightning and his new ball!