How does Data Cloud integrate with Marketing Cloud Connect?

Data Cloud and Marketing Cloud integration works bidirectionally via the Marketing Cloud Connector:

1. Segment Activation to Marketing Cloud Journey Builder (JB) — a Data Cloud Activation Target pushes segment members into Marketing Cloud as a contact list or Journey Entry Event Source. When a new member enters the segment, they are automatically enrolled in the linked Journey. Attributes mapped during activation are available as Journey data extensions for personalization.
2. Engagement Data Back to Data Cloud — Marketing Cloud sends email engagement events (sends, opens, clicks, bounces, unsubscribes) back to Data Cloud via the Marketing Cloud Connector as Engagement DMO records. This closes the loop, enriching the Unified Profile with channel engagement history and enabling re-segmentation based on email behavior.