Just like cancelled subscriptions, a canceled trial means the same: the user opts-out from prolonging the subscription. That means you won't get the first payment (or any other until the user restores their subscription).
Apple/Google will let you know about the cancelled trials via server2server notifications. Handle, store, and process them to build custom views with the cancelled trial analytics.
Adapty does everything for you automatically. Simply install the SDK for your platform, open the Advanced dashboard, and check all the data!