Marketing Cloud should be the single source of truth for customer journey flow, which is the sequence of interactions that a customer has with a brand across different channels and touchpoints. Marketing Cloud can help design, execute, and optimize customer journeys using Journey Builder, which can leverage data from other systems, such as B2C Commerce or Service Cloud, to trigger or personalize journeys. Reference: https://help.salesforce.com/s/articleView?id=sf.mc_jb_journey_builder.htm&type=5