How to cancel Amazon Fire Stick subscription?

Is this a subscription that you took out through Apple? Or a subscription that you took out directly from Amazon? If it's something you took out through Amazon's Web site or an Amazon device, you may need to go to Amazon's site to cancel it.

https://www.amazon.com/yourmembershipsandsubscriptions

There is an Apple article that explains how to cancel subscriptions. Click on the following link: If you want to cancel a subscription from Apple - Apple Support