Hadronic decay of tau lepton

There has been a 3+ sigma deficit of the Cabibbo-Kobayashi Masukawa (CKM) 3-family-unitarity reported from the inclusive hadronic decay of tau lepton. We propose and apply a novel dispersive approach to determine the CKM matrix element Vus using inclusive hadronic tau decay data, and lattice QCD to address the issue of the quark-hadron duality violation. In addition to the results of the new analysis, other related topics of the inclusive hadronic decays and lattice QCD will be discussed.