Fujifilm GFX 50S II has a Fujifilm G lens mount and currently there are 18 native lenses available for this mount.
The latest released lenses that are compatible with the GFX 50S II are the Fujifilm GF 110mm F5.6 TS Macro, the Fujifilm GF 30mm F5.6 TS and the Fujifilm GF 55mm F1.7R WR.
GFX 50S II also has a sensor based image stabilization system which means that all of these lenses will be stabilized when used on the GFX 50S II.
Since Fujifilm GFX 50S II has a Medium format sensor, it has a focal length multiplier of 0.79x so you have to multiply lenses original focal length with this multiplier to find the Full Frame equivalent focal length of the lens when mounted on GFX 50S II.
You may also also be interested in these:
Fujifilm GFX 50S II Lenses with Image Stabilization
Fujifilm GFX 50S II Lenses with Weather Sealings