The latest DLC pack for XCOM 2, Shen's Last Gift, will turn Chief Engineer Lily Shen into a proper unit on the battlefield.
A hidden ADVENT facility has been discovered, spread throughout several skyscrapers connected by bridges, and only she can analyze and assess the high-tech weaponry hiding inside. In this ADVENT "Lost Towers" facility, Lily Shen will find the remnants of her late father's final project (her father was in the first XCOM). This will perhaps lead you in discovering a new soldier class in your fight against the alien establishment.
Hey, XCOM 2 is all about stealing and adapting alien technology, so this is just par for the course. Of course, it's not going to be easy taking the ADVENT's technology out from under them, as there is word of an ADVENT MEC (perhaps several) in the facility.
Shen's Last Gift can be purchased separately for $9.99 or will come included in the Reinforcement Pack. Just don't buy both or you will be charged twice. The Mac and Linux versions of the DLC will be available soon.