Put his litter box on your porch, along with an article of clothing with your scent on it. Cats have a wonderful sense of smell and will come to those items. Leave a window cracked nearby so that you can hear him. Post pictures around the neighborhood and on doors. Ask neighbors to keep an eye out and to check garages and sheds. Cats hide, usually fairly close by. They tend to come out after dark, so look for him then. Call and rattle a treat can if he likes those. If you put food out, stay close by, because it will also attract other animals that might scare him away. Don't leave it out very long. Also, go in person to shelters and vets' offices, and leave a picture and phone number there. I hope you find him!
Make “Have You Seen Me?” fliers with picture and phone number. Duct tape them to power poles. Knock on doors and talk to your neighbors. Ask them to check garages, under sheds, etc. Tape fliers with scotch tape to front doors. Check your local shelter and leave your info with them. Check back if necessary. Walk the neighborhood calling for them. Walk at night if this is a cat. Walk with a leash if this is a dog. Cats don’t usually go far but it may take a few days. I’ve had dogs get loose and had a cat with an attitude jump out of a bedroom window. I always found them. Good luck. ❤️