Quark-gluon dynamics: what we don't know

We have learnt a lot on the internal structure of nucleon through decades of investigations in high energy experiments, including parton distributions, quark and gluon helicity distributions, and some aspects of the generalized parton distributions and transverse momentum distributions. In this talk, we will summarize what we don't know on the partonic structure of nucleon, focusing on new phenomena, new structure, new dynamics which we can obtain in the planned experiments in the future.