Dirac cones are generically tilted when realized in a realistic material. This gapless structure is effectively protected by the generalized chiral symmetry. It induces topological edge states when the system has boundaries. Bulk-edge correspondence for this case is described in Phys. Rev. B 103, 205306 (2021) by T. Kawarabayashi and Y. Hatsugai. See also arXiv:2011.09164.