If you already haven’t done some of these things, call the police to give them pup’s description, call vets, shelters, put out flyers in waterproof envelopes. Post on “Lost Dogs Illinois”. If microchipped, make sure information is correct. Also, in addition to Facebook, post on any social media sites you know. Check with your neighbors. Many dogs are found within a two-mile circle of their home. So mark a circle with your house in the middle.
Prayers you find him.