Inkang Kim works on hyperbolic geometry and symmetric spaces. He works on rigidity and flexibility of discrete groups acting on symmetric spaces. For rigidity side, he proved the marked length rigidity of Zariski dense subgroups of semisimple Lie groups. In the line of Weil's local rigidity, with his collaborators he proved the local rigidity of real and complex hyperbolic lattices in quaternionic hyperbolic spaces. For flexibility side, with Pierre Pansu he characterized the criterion for a deformability to a Zariski dense representation of a surface group representation in semisimple Lie groups. Specially in hyperbolic 3-manifolds, with other collaborators he generalized William Thurston's double limit theorem to any hyperbolic 3-manifold with compressible boundary.[-]