Collaborative Apple Music playlists, a feature that Apple has promised for iOS 17, won't be coming in 2023. With today's iOS 17.2 release, Apple updated its iOS 17 features list [PDF] to note that the option to collaborate on playlists has been delayed.
Apple tested collaborative playlists in the early iOS 17.2 betas, but ended up removing the feature in the fourth iOS 17.2 beta. There were likely bugs in the option that Apple was not able to remedy in time to bring the feature to iOS 17.2, and as iOS 17.2 will be the last publicly available update to iOS 17 in 2023, we won't be getting collaborative playlists until 2024.
In the iOS 17.2 beta, playlists gained a "Collaborate" option that created a link to a playlist, and anyone with access to that link was able to add to the playlist. Users had control over who was able to contribute, with an option to approve each person that asked to join and tools for removing users.
It is not clear when collaborative playlists in Apple Music might launch, but we will likely get an iOS 17.3 update in January, with testing to begin in December.
While collaborative playlists did not come in the iOS 17.2 update, Apple did add a Favorites Apple Music playlist that aggregates songs that are favorited.
Source: Macrumors