You are right on track: this technique and its derivative style are called [**cell shading**][1], named after the transparent celluloid sheets that are used in classical comic and animation production:

<img src="https://i.sstatic.net/rtvF1.png" width="350" alt="cel sheet with Donald and Mickey"/><br><sup>[source][3]</sup>

These sheets are used to separate animation from the inanimate background and static props. On them, the outlines are usually drawn on one side, and the objects coloured in on the back, giving crisp outlines.  
These outlines are rendered in 3D using edge detection, to simulate a flat character.

Fun fact: Telltale introduced this signature style in The Walking Dead season 1 as they wanted to imitate the comic art by [Tony Moore][4]. 


  [1]: https://en.wikipedia.org/wiki/Cel_shading

  [3]: https://animationbasketcase.wordpress.com/2015/05/27/celluloid-animation/
  [4]: https://en.wikipedia.org/wiki/Tony_Moore_(artist)