
This trailer really annoys me.
Reason being, it takes what should be a remarkable thing–reintroducing Neanderthals into the present day–and instead appears to be little more than a typical play on being a member of an “out group” (depending upon the circumstances, a woman, people of color, smart people, homosexual, etc) learning how to fit into a society that cares only about superficial things (like one’s appearance).
As you can gestimate from the image and trailer, William’s most prominent physical feature seems to be a prominent brow ridge, which isn’t as unusual as the movie makes it appear.
Your want evidence? Here’s a clip from Huey Lewis and The News’ Heart & Soul, from 1983.

Notice the (somewhat) prominent brow ridge? Now I wouldn’t be surprised if she received some mocking growing up, but to be fair, who didn’t?

This is Michael Berryman, a renown actor who’s done work with everyone from Wes Craven to Miloš Forman, so you can tell distinctive facial features doesn’t necessarily mean you cannot be successful at whatever you happen to be doing.
Though to be fair the movie posits that William was a celebrity of sorts, so the movie likely documents his trying to fit in.
Which isn’t to say that we haven’t seen this before, but with a Neanderthal.