If you can get a live trap that will help. Have neighbors check all garages and sheds in case he got stuck in one. Also check sewers and in trees because a lost cat was recently stuck in one. And under porches. At night go outside with a flashlight and some treats or a bag of cat food and call for him.You can also play ringtones of kittens meowing- he might hear it. Shine the flashlight in bushes so you can see his eyes glowing. Many people have found their lost pets between midnight-6 am. Be sure to check all surrounding shelters,rescues and vets in case someone found him and brought him there. Also check with your mail carrier as they see alot on their routes. Check all closets,drawers,crawl spaces,bat,attic,inside recliners and inside and behind the couch in case he hid and got stuck.Go outside when its dark with a laser pointer and point it to the ground-he might see it. If you have a baby monitor put it outside so you can hear him. Leave your garage door up a little bit and put some food in there so he can go in. And most importantly- do NOT listen to anyone who tells you to text a number or code or to go onto Instagram or FB for "pet rescuers", "pet trackers" or "pet detectives" because they're scammers preying on pet owners and should be reported and banned.