Normally, in Blender 2.7 when you open the SIMS 4 Studio rig, you'll be able to see it's skin or material in Material View immediately.
But in Blender 2.8 that's not the case.
What you have to do:
1. Change the render engine from Eevee to Cycles.
The location of this setting is on the Properties panel > Render Settings Tab (with camera icon).
2. Make the rig becomes selectable.
On the outliner panel, make one of the body mesh selectable.
If the select icon didn't appear, make sure on the filter (below) the select icon is activated
3. Click on a body mesh in 3d View - Object mode, then in the properties panel, a Material Properties Tab will appear. Click it.
4. In the subdivision - Surface change the settings as follows:
*These settings won't appear if you haven't change the render engine from Eevee to Cycles.