Microsoft-optimized headsets, also referred to as -M, MOC, or OCS versions, are the same as the standard UC headsets with one exception.  Microsoft-optimized headsets have call control with Microsoft Lync and Skype for Business right out of the box built into the headset without needing to download additional Plantronics headsets.

Additional Resources:

Microsoft Lync Quick Setup Guide

Plantronics Unified Communications Portfolio for Microsoft