Alright, friends here is what I did last week,

One interesting feature that came with SQL Server 2016 that can be of good use to us is that we can compress the DB’s backup even if we have TDE enabled on them. There is a small switch that we need to change for doing as it does not pick up compression directly.

For this to work with TDE-enabled databases, the MAXTRANSFERSIZE backup parameter should be set to a value larger than the default 65536 value. MAXTRANSFERSIZE specifies the largest unit of data transfer in bytes that is used to transfer data between SQL Server and the backup media, with possible values equal to multiples of 65536 bytes (64 KB) and a maximum value equal to 4MB.

Explained here –

https://blogs.msdn.microsoft.com/sqlcat/2016/06/20/sqlsweet16-episode-1-backup-compression-for-tde-enabled-databases/