The GET /card-onboarding-sessions/{cardOnboardingSessionId} endpoint allows clients to track the progress of a card onboarding session, retrieve customization details, and check expiration status. It is useful for resuming onboarding flows or debugging session failures.

Implementation Guide:

1. Initiate a card onboarding session using the appropriate API.
2. Store the cardOnboardingSessionId returned from the session creation API.
3. Use this GET endpoint to periodically check session status or retrieve UI customization settings.
4. If the session is incomplete, prompt the user to complete onboarding before expiration.