I found this website , I think is from Penn State and NSF. it a project that describe the Chern Simons theory's role.
Chern-Simons theory:prediction of composite fermion, a new class of topological fermions in physics. what is special about them? is the question in the outline.
The Chern-Simons theory unifies the fractional quantum Hall with the well understood integral quantum Hall effect, in the process leading to the prediction and the subsequent discovery of a new class of topological fermions in nature.