Last year was Sony's year; Nikon is coming in hard this year with their D500 and its pro level specs or "prosumer" and the announcement of the D5 with its ability to see dead people having an ISO of 3,280,000.
Nikon's first push into the waterproof / shockproof world was really with the AW100 which took god awful pictures but amazing videos. Knowing this comes from the fact that some of FishingKaki.com's videos were actually shot with an AW100, they are now up to the AW130 the last I checked and have further pushed with the S33 a budget version. There is also the Nikon 1 AW 1 which is also waterproof / shockproof with the option to change lenses. Pretty cool huh.
For those who have not dabbled in 360 videos, it give the ability to shoot all around and with current view-tech, allow the user to scroll or swipe around the video. It is present in Facebook, YouTube and even Vimeo. They are also known as 360 spherical videos.
click and drag around the video
Of course Nikon is not the first to go into 360 video recording, the ever popular GoPro has a mount called the Freedom360. While it frees you to do 360 video taking, it does not free your wallet from the damage it does from the 6 GoPros you are going to need.
As for the 4K 360 KeyMission, Nikon has not released specs or pricing as CES 2016 winds down.
With things like wearable VR (Oculus Goggles) and Drone videography going mainstream I am expecting a whole lot of video tech coming to the world in 2016.