Mercedes engineers have reportedly begun picturing what the future S-Class that will replace the W222 model will look like. The final product is expected to debut sometime in 2021. As of now, everything is still in the development process although chief engineer Hermann-Joseph Strop did reveal this:
"It may be that the next S-Class has more aluminium, or aluminium combined with plastics [CFRP], for example."

" [The] discussion we have with weight; the other is stiffness for the body, and reducing noise. [The] reduction of weight, CO2 reduction, the combination of [a] combustion engine with plug-in electrical power, new batteries... and drag coefficient – to reduce it as far as we can – will again help [the new S-Class]."
[Motoring]