Just like that Cyanogen begins work on CM13. With every new version of Android comes a new version of Cyanogenmod. We are only one week past the official release on Marshmallow, and this time around Cyanogen has jumped on development quickly. The move to Lollipop was slower going as the CM team focused heavily on finishing up Kit Kat development in favor of LP development.
It should be noted that the work has only just begun. There are no test builds as of yet. Those test builds should be pushed out in the coming weeks. Remember early builds won't be the most stable and may have some bugs. It is nice to see the quick turnaround here though!
via CyanogenMod