Cyanogen has released the CM 12.1 Nightlies, which are based on Android 5.1 Lollipop.
The new ROMs are already available for dozens of devices.
You can download the nightly builds from Cyanogenmod’s official website.
Disclaimer: These versions are not recommended to be used as a daily driver. They could still have bugs.
Cyanogen says that users can install the new versions on top of official CM12 ROMs, but you will need to find and flash a working GAPPS (Google Applications Package). You can look around for them at the XDA forums
The ROM maker had some words about the deal which they signed with Microsoft, and was announced yesterday. More on this here.