The Lenovo ThinkPad T480s isn't just a slimmer T480
It's better to think of it as a more premium version of the T480. It's slimmer, but it's also made from a carbon fibre composite which makes it not only lighter, but stronger too. The T480s also supports quick charging, for an 80% charge in just one hour. One RAM module is soldered though, so the maximum is 24gb rather than 32gb for the T480.