Print Jobs stuck with status 'Pending'

Pending typically means Universal Print is waiting for the printer to pickup the job. You can learn more about states here - Print Job Status - Universal Print | Microsoft Learn.

There could be multiple reasons why printer may not be picking up jobs. For example, Universal Print ready printer may have lost connectivity and is unable to restore the notification channel. In Connector case, it might be because a previous job on the same printer is being processed etc. 

If you cannot find a good reason to explain the state, then I recommend reaching out to Microsoft Support team.