If you no longer want to be subscribed to GymYou pro, you can cancel it in your Apple account.

1. Open the Settings app on your iPhone.
2. Tap on your name.
3. Tap subscriptions.
4. Find the GymYou subscription.
5. Tap Cancel Subscription. You might need to scroll down to find the Cancel Subscription button. If there is no Cancel button or you see an expiration message in red text, the subscription is already canceled.

Be aware that you should cancel your subscription no later that 24 hours before your subscription period renews.

If you can’t find the subscription you want to cancel, you might this article from Apple helpful.