Update - On March 4th we revealed Peloton Sessions would be returning soon, thanks to a FAQ page update, and will contain an integration with Scheduling. On March 9th, Peloton began to tease the return too.
In the winter of 2020, Peloton released a new feature known as Peloton Sessions. This was described as a limited time beta when it launched, but not much more was said. The feature allowed people to join classes together and have the leaderboard synced up. After less than a month, the feature was removed.
When it was removed, Peloton stated "we’ll make it even better when it’s officially released." - confirming that Peloton Sessions would return. However, the exact date has not been confirmed, but it looks like it will be early March.
Now that the Peloton scheduling feature has been released, there is the potential for Peloton to integrate it more closely with Sessions when it returns. For example, it could be updated so that the class you schedule is a private session for you and the friends you invited to it.