Dawn & Dusk. These are the times that cats are most active, in search of food.
Go out searching at these times of day.

Put a dirty shirt of yours (or his human at home) on the porch.

Is he 'chipped'?

Check the shelters, vets. Ask to go in the back and look for him.

Cats can come home, days, weeks, months, and years later.

Stay strong.