Comparing the two interiors, you can see the lack of design in the CLS as it mimicks every other Mercedes product that year
2018 CLS interior :
Looking at similar model year BMW: unique cabin design featuring a waterfall effect cockpit design making it both unique and stunning, best interior design we've had in the last little while. New 8 series doesn't even have this level of differentiation from the rest of the BMW lineup
2018 6 series interior :