It's probably just some personal items rattling around in the console storage area.
Modern cars (and the CX-5 is one of the most modern) have everything attached in such a way as to minimize the chances of rattles/squeaks. Even though modern cars have many times more motors, cameras, heated this, lighted that, multiple speakers, etc., there are less squeaks and rattles than on cars of the 1970's that came with one speaker, nothing heated, etc. I've not heard one squeak or rattle from my 2013 CX-5, even after driving it for miles on rough logging roads and railing it near the limit of tire adhesion on twisty roads.
Taut little chassis.