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.
Note: Once the subscription has been canceled, you will no longer have access to any courses that were enrolled in and/or completed during the duration of the Annual Membership subscription.
For in-app subscriptions through Apple or Google Play, cancelations can be managed through the respective App stores in the subscription sections.