  Recently, a new hidden-charm pentaquark state $P_{cs}(4459)$ was reported by
the LHCb Collaboration. Stimulated by the fact that all hidden-charm pentaquark
states in $S=0$ systems were successfully predicted by our chiral quark model,
we extended this study to the $S=-1$ systems. All possible quantum numbers
$IJ^P=0(\frac{1}{2})^-$, $0(\frac{3}{2})^-$, $0(\frac{5}{2})^-$,
$1(\frac{1}{2})^-$, $1(\frac{3}{2})^-$ and $1(\frac{5}{2})^-$ have been
investigated. The calculation results shows that the newly observed state
$P_{cs}(4459)$ can be explained as $\Xi_c \bar{D}^*$ molecular state and the
quantum number is $0(\frac{1}{2})^-$. In addition, we also find other molecular
states $\Xi_c \bar{D}$, $\Xi_c^* \bar{D}$ and $\Xi_c' \bar{D}^*$. It is worth
mentioning that $\Xi_c \bar{D}^*$ can form a two-peak structure from states in
system $0(\frac{1}{2})^-$ and $0(\frac{3}{2})^-$. The decay width of all
molecular states is given with the help of real scaling method. These
hidden-charm pentaquark states is expected to be further verified in future
experiments.
