  Inspired by the very recently discovered tetraquark states $T_{c\bar s
0}^a(2900)^{0,++}$ from the LHCb Collaboration, we predict the existence of a
new charmed-strange pentaquark system, $c\bar s nnn$, which is closely
connected to $c\bar s n\bar n$ by exchanging $\bar n$ into $nn$ with $n=u,d$.
Especially, it is suggested to experimentally search for the predicted new
pentaquark system via the weak decays of $B$ mesons or $b$-baryons, with the
support from the study of the mass spectrum and the decay properties. The
predicted new pentaquark system must attract extensive attention from
experimentalists and theorists when it constructs the ``particle zoo 2.0" in
the near future.
