  The semileptonic decays of the open charm-bottom axial-vector tetraquark $
Z_{s}=[cs][\overline{b}\overline{s}]$ to $X(4274)\overline{l} \nu_l$, $l=e,
\mu, \tau $ are explored by means of the QCD three-point sum rule method. Both
$Z_{s}$ and $X(4274)=[cs][\overline{c}\overline{s}]$ are treated as color
sextet diquark-antidiquark states. The full width of the decays $Z_s \to
X(4274)\overline{l} \nu_l$ is found. Obtained predictions for $ \Gamma(Z_s \to
X(4274)\overline{l} \nu_l)$ demonstrate that, as in the case of the
conventional hadrons, the semileptonic transitions form a very small part of
its full width.
