Consider interfaces and dependencies between what is happening within the ISMS scope and the outside
Interfaces are the limit points between what is inside the ISMS scope and what is out (e.g., a website page is an interface between organization's information systems and the external public, a loading area is an interface between a supplier and the organization, etc.).
Dependencies are relations between organization's elements (processes, assets, etc.) that are needed to achieve a defined outcome (e.g., a datacenter depends upon a communication provider to make information systems available).