More details are on https://powerbi.microsoft.com/en-us/blog/power-bi-september-2020-feature-summary/
As data volume continues to grow, so does the challenge of wrangling that data into well-formed, actionable information.
Analysts can easily create dataflows, using familiar, self-service tools. Dataflows are used to ingest, transform, integrate, and enrich big data by defining data source connections, ETL logic, refresh schedules, and more. In addition, the new model-driven calculation engine that’s part of dataflows makes the process of data preparation more manageable, more deterministic, and less cumbersome for data analysts and report creators alike.
Read more in the article from Adi Regev, Principal Group Program Manager, Power BI dataflows