  We consider the U(1)$_X$ model, which can induce the flavor violating
couplings through vectorlike fermions and address the observed rare $B$-meson
decay anomalies. To be consistent with all the other observations, both the
associated gauge boson mass and the vectorlike lepton mass are bounded from
above. We argue that the search for new vectorlike leptons is promising and
provides a complement to the $Z'$ search. A detailed collider analysis shows
that the model with the vectorlike lepton mass up to 1000 GeV could be tested
at the future LHC.
