How does the 3d model sustain a black outline when it rotates from all angles? I heard it involved model dublication, cant figure it out.
Since Blender was tagged in that insta link so at a guess the model is first drawn via either a 2.79 or 2.8x grease pencil technique, similar too those authored by Jama Jurabaev including the 360 turntable:
This is most probably simply the freestyle renderer. That’s the included cartoon renderer.
Nowadays you could also use the LineArt modifier in conjunction with a grease pencil object. But not sure about the performance with animation. And never did it yet.