How do I unlink a shared Apple Music subscription from my iPhone?
The Apple Music subscription was shared with my phone, but I don’t want to continue having that shared subscription. How can I remove it?
[Re-Titled by Moderator]
If this is your own subscription, you can cancel it: If you want to cancel a subscription from Apple - Apple Support
If this is part of a Family Sharing group, you can ask them to stop sharing the subscription, or stop using Family Sharing: Leave Family Sharing - Apple Support
In an extreme case, you can use a secondary Apple Account for Media & Purchases.