Yes! Once you've signed up for the annual membership through masterclass.com, you can cancel the auto renewal at anytime by heading to https://www.masterclass.com/account/edit. Select Cancel button in the Subscription section of the page, and the cancel subscription page will appear. On the page, select continue to cancel. Your account will not renew at the end of your current subscription period.
For in-app subscriptions through Apple or Google Play, cancelations can be managed through the respective App stores in the subscription sections.