Walking Animation in Unity NOT WORKING

So, I made a walking animation in Blender and it works here: Mario Joined - 3D model by yangjosh [e1d4e53] - Sketchfab

However, when I import it into Unity and replace the thirdpersoncontroller mesh with the model in the URL above, the walking works perfectly, however, there is no animation whatsoever.

Anybody know what’s wrong?

Of course. You did placed mesh but did not setup animations. Those are different assets. Please, visit Learning Section and find out how it is done properly.