A canary release gives a new version of an app to a small group before making it available to everyone. It is like trying a new recipe with a few guests first, then serving it to the whole table if it goes well.
A team can watch for errors or other problems among the first users. If things look healthy, they can gradually expand access; if not, they can stop the rollout and investigate.
The first group may not experience every situation, so teams still need broader checks as the release grows.