Where is the cabin air filter on 2008 GMC Sierra 1500?

The cabin air filter on a 2008 GMC Sierra 1500 is located behind the glove compartment. To access it, you need to open the glove compartment and remove any contents, then gently squeeze the sides of the glove box to release it from its hinges. Once the glove box is lowered, you can remove the cover to reach the cabin air filter.