Row -Level Security or managing roles in Power BI is not something new. But environments, where there is a need for securing read access for end-users based on their account name, are very frequent. Row Level Security is omitting and controlling access to a user or group (or distribution group in active directory) to rows on a single dataset (or table in SQL Server) and all the relationships to this dataset.
There is a performance cost to this, but if you need it, it’s there. Power BI row-level security can also work with Analysis Services row-level security and (to an extent, and this is new) SQL Server row-level security.