Graphics Settings (XCOM 2)

SSS: Subsurface scattering is an energy (light) transfer mechanism in which light, penetrating through the surface of a translucent material, is scattered inside the material itself and exits the material at another point. Scattering occurs by multiple reflections in a random direction from material particles.

Subsurface scattering must be used for the correct rendering of materials such as marble, jade, wax (paraffin), leather, etc.

In general, Google will help