Fuji’s mirrorless lineup has been around for long enough now that the lens lineup is pretty well fleshed out. Despite the lack of 3rd party manufacturers (although Sigma’s rumoured to be working on it), Fuji’s managed to do quite well on its own to meet the needs of their customers. But there are some gaps.
Fuji only has one super-telephoto zoom (the XF 100-400mm f/4.5-5.6) and no really long primes. According to a report on FujiRumors, though, it seems that Fuji’s working on another long super-telephoto zoom, that’ll offer a focal length range of 150-500mm. This would provide a similar field of view on Fuji cameras to that of a 225-750mm focal length range on a full-frame body.