  Recently, for the first time, the BESIII Collaboration reported the strange
hidden charm tetraquark states $Z_{cs}(3985)^-$ in the $K^+$ recoil-mass
spectrum near the $D_{s}^{-}D^{*0}/ D_{s}^{*-}D^{0}$ mass thresholds in the
processes of $e^{+}e^{-}\to K^{+}(D_{s}^{-}D^{*0}+D_{s}^{*-}D^{0})$ at
$\sqrt{s}=4.681$ GeV. The significance was estimated to be 5.3 $\sigma$. We
show that the newly observed $Z_{cs}(3985)^-$ state is the $U$-spin partner of
$Z_c(3900)^{-}$ as a resonance within coupled-channel calculation in the
$\text{SU(3)}_F$ symmetry and heavy quark spin symmetry (HQSS). In the
$\text{SU(3)}_F$ symmetry, we introduce the $G_{U/V}$ parity to construct the
flavor wave functions of the $Z_{cs}$ states. In a unified framework, we
consider the $J/\psi\pi(K)$, $\bar{D}_{(s)}{D}^*/\bar{D}_{(s)}^*{D}$
coupled-channel effect with the contact interaction. With the masses and widths
of $Z_c(3900)$ and $Z_c(4020)$, we determine all the unknown coupling
constants. We obtain mass and width of $Z_{cs}(3985)$ in good agreement with
the experimental results, which strongly supports the $Z_{cs}$ states as the
$U/V$-spin partner states of the charged $Z_c(3900)$. We also calculate the
ratio of the partial decay widths of $Z_{cs}(3985)$, which implies that the
$\bar{D}_sD^*/\bar{D}^*_s D$ decay modes are dominant. We also predict the
$Z_{cs}^\prime$ states with a mass around $4130$ MeV and width around $30$ MeV,
which are the $U/V$-spin partner states of the charged $Z_c(4020)$ and HQSS
partner states of the $Z_{cs}(3985)$. In the hidden bottom sector, we predict
the strange tetraquark states $Z_{bs}$ and $Z_{bs}^\prime$ with a mass around
10700 MeV and 10750 MeV, which are the $U/V$-spin partner states of
$Z_{b}(10610)^{\pm}$ and $Z_b(10650)^{\pm}$, respectively.
