I'm sorry your cat is missing. Please put their litterbox outside so they can smell home. Hand out fliers to neighbors and ask if they have heard noises in their garages or sheds. Post on nextdoor, lostmykitty, craigslist, pawboost, and petharbor. Go around at night and squeak or make sounds with their favorite toy while calling for them. Is your cat chipped? Have you reported them missing to the chip company?