Seems like the same camera — with cosmetic and UI/UX differences:
Leica SL2 as simpler, better aesthetics
SL2 also seems thinner, probably lighter.
Which to get?
If you want a sexier body, and more luxury approach, get LEICA SL2.
If functionality is all you care for, get Lumix S1R.
I believe both cameras share the same sensor.