If you own a pair of AirPods Pro that produce crackling or static sounds, then Apple will replace them for free. The replacement program also applies to units where active noise cancellation is not working as expected. Apparently, a design flaw is the reason why some of these issues have been occurring.
https://www.notebookcheck.net/Apple-starts-replacing-AirPods-Pro-for-free-because-of-a-design-flaw.501640.0.html