Use pending leads as a "pre-lead" status and open them when you are ready to start working on them.
Typically, leads are in one of four statuses: open, won, lost, or canceled. It's also possible to place a lead into a pending status.
Pending leads are used specifically for the workflow of importing huge batches of leads, then opening them and assigning them to your team members at a pace that makes sense. Use the bulk edit tool to convert pending leads into open leads.
Pending leads are not assigned to a user, and are not considered part of your pipeline. They are not included in your reports until you open them.