The pending status is assigned to subscribers who have not yet confirmed their subscription to your newsletter.
For this reason, subscribers enter the pending status if your publication has “double opt-in” turned on. They also enter this status if they sign up through a referral (to prevent users from gaming the system for your referral rewards).
The pending status looks like this in your subscriber list or segment:
Please note: users who are in the pending status will not receive any emails from your newsletter (no posts, no emails to a segment, and no welcome email/sequences) until they have confirmed their email address.
The purpose of double opt-in is to act as a filter preventing poor fit subscribers, or fake subscribers, from receiving easy access to your publication.
This helps you build a high quality list of subscribers.
It is often the case where these poorly engaged subscribers hurt open rates and deliverability. Turning on double-opt-in limits the possibility of poor fit subscribers hurting these key metrics.
It is normal to have users in the pending status forever (some subscribers may never confirm their email).