Since Lenovo already has a Tango 3D-capable handset on the market, seeing a Moto Mod capable of offering augmented reality to the Moto Z would not be a surprise. However, remains to see when will it happen.
http://www.notebookcheck.net/Lenovo-Moto-Z-expected-to-get-a-Tango-3D-camera.186461.0.html