  We present a combined angle-resolved photoemission spectroscopy (ARPES) and
first-principles calculations study of the electronic structure of LaAgSb$_2$
in the entire first Brillouin zone. We observe a Dirac-cone-like structure in
the vicinity of the Fermi level formed by the crossing of two linear energy
bands, as well as the nested segments of Fermi surface pocket emerging from the
cone. Our ARPES results show the close relationship of the Dirac cone to the
charge-density-wave ordering, providing consistent explanations for exotic
behaviors in this material.
