Stretch DB feature in SQL Server 2016 helps to move a part of a SQL Server table to the azure for Archival.
It would help in situations where there is a need to archive non transactional Rows from a table, but still need the ability to Query them when needed.
Watch this video for more details.
More Info:
https://msdn.microsoft.com/en-us/library/Dn935011.aspx