He/she won't be far away. Go out at night with flashlight and look for shiny eyes. Leave an opening so he/she can get back into your house. Check nearby (within 3 typical city blocks) sheds, containers, hidey holes, garages. Put up posters for folks in the area who are not on line. A nice neighbor might have let him/her in. Also please do not forget to post to 719 Lost and Found Pets of Colorado Springs, Colorado Springs Lost Pets Facebook page, Pawboost, the Humane Society, and Nextdoor (a free app for folks near your house). Finally, go to catsinthebag.org for ideas on how to find him/her and get him/her back home.