They'll probably look a lot like this.
This technology is called Separable Subsurface Scattering. It's the product of "hours and hours of research, desperation, excitement, happiness, pride, sadness and extreme dedication" on the part of researchers Jorge Jimenez and Diego Gutierrez, and it's designed specifically to be used for human skin in video games.
Not trailers, not movies, not cartoons, but video games. SSS has been written entirely in DirectX 10, and everything you see is being rendered in real-time. Don't believe them, you can download the original demo here and try it yourself.
If you watch the clip and find yourself a little underwhelmed, that might be because it was designed to run fullscreen at 1080p. So try it out as nature intended for the full effect.