The GF mount lenses are for the Fujifilm medium format camera (GFX 50s). The format has a focal length equivalence (to 35mm film) of 0.79x. Fujifilm launched the format with six announced lenses, three of which were available at first shipment of the body. two of which will be available in mid-2017:
In addition, there is an H-mount adapter that allows you to mount old GF645AF lenses (Hasselblad 1) to a GFX 50s. Such adapted lenses can use their leaf shutter up to 1/800. Manual focus only, though the electronic communication between camera and lens is otherwise maintained.
Fujifilm has announced a roadmap that includes a new telephoto prime and a teleconverter to be introduced in 2018.