Nikon has started developing a new Nikkor Z 800mm f/6.3 VR S super-telephoto lens with a constant focal length for Nikon full-frame mirrorless cameras with a Z-mount. The optical scheme of this lens uses a Fresnel lens. This design is found for the first time in Nikon optics. The use of Fresnel lenses can significantly reduce the size and weight of super-telephoto lenses. The Nikkor Z 800mm f/6.3 VR S lens will be of interest to wildlife photographers. We are waiting for technical specifications, prices and release dates from Nikon.
Also look at the review of the Nikon Z 28-75 mm f/2.8 lens.