You can cancel your KineMaster Premium subscription by following these steps:

1. Open the Settings app
2. Tap on your Apple ID
3. Tap Subscriptions >> KineMaster >> Cancel Subscription.

When you cancel a subscription, you’ll still be able to use your subscription for the time you’ve already paid for.

Note: Uninstalling KineMaster will not cancel your subscription. Should you uninstall KineMaster without cancelling your subscription, you will still be charged— you must actively unsubscribe following the process above.

For more information, please visit the following site:
https://support.apple.com/en-us/HT202039