DAX security filters
DAX can also be used for implementing security within a Power BI model. When a user retrieves a report, they will be able to see all results provided by the model through that report. In many cases, there is a need to restrict what the user sees, based on their role or identity. For instance, consider the DAX security expression below:
Customer[Region] = "Europe"
When set for a specific security role, this DAX security filter will cause users in that role to only see customers in the Europe region, together with data related to those customers.
Chapter 2.1 further introduces security with DAX.