Panasonic S5 II X has a Leica L lens mount and currently there are 62 native lenses available for this mount. S5 Mark II X also has a sensor based image stabilization system that is up to 6.5-stops effective which means that all of these lenses will be stabilized when used on the S5 Mark II X.
Since Panasonic S5 II X has a Full frame sensor, it has a focal length multiplier of 1x so lenses will provide their original focal length on S5 Mark II X.
You may also also be interested in these:
Panasonic S5 II X Lenses with Image Stabilization
Panasonic S5 II X Lenses with Weather Sealings