The motivic Chern class in K-theory is a generalization of the Chern-Schwartz-MacPherson class in homology. As the affine Hecke algebra, the motivic Chern classes of Schubert cells have a Langlands dual description. In joint works with P. Aluffi, L. Mihalcea, and J. Schurmann, we use this description to solve some problems about the Casselman basis for the p-adic dual group, and relate the Euler characteristic of the motivic Chern classes to the Iwahori-Whittaker functions.