  We consider a class of SUSY models in which the MSSM gauge group is
supplemented with a gauged $U(1)_{B-L}$ symmetry and a global $U(1)_{R}$
symmetry. This extension introduces only electrically neutral states, and the
new SUSY partners effectively double the number of states in the neutralino
sector that now includes a blino (from $B-L$) and singlino from a gauge singlet
superfield. If the DM density is saturated by a LSP neutralino, the model
yields quite a rich phenomenology depending on the DM composition. The LSP
relic density constraint provides a lower bound on the stop and gluino masses
of about 3 TeV and 4 TeV respectively, which is testable in the near future
collider experiments such as HL-LHC. The chargino mass lies between 0.24 TeV
and about 2.0 TeV, which can be tested based on the allowed decay channels. We
also find $m_{\tilde{\tau}_{1}}\gtrsim 500$ GeV, and
$m_{\tilde{e}},m_{\tilde{\mu}},m_{\tilde{\nu}^{S,P}} \gtrsim 1$ TeV. We
identify chargino-neutralino coannihilation processes in the mass region $0.24
\,{\rm TeV} \lesssim m_{\tilde{\chi}_{1}^{0}}\approx
m_{\tilde{\chi}_{1}^{\pm}}\lesssim 1.5$ TeV, and also coannihilation processes
involving stau, selectron, smuon and sneutrinos for masses around 1 TeV. In
addition, $A_{2}$ resonance solutions are found around 1 TeV, and $H_{2}$ and
$H_{3}$ resonance solutions are also shown around 0.5 TeV and 1 TeV . Some of
the $A_{2}$ resonance solutions with $\tan\beta \gtrsim 20$ may be tested by
the $A/H\rightarrow \tau^{+}\tau^{-}$ LHC searches. While the relic density
constraint excludes the bino-like DM, it is still possible to realize higgsino,
singlino and blino-like DM for various mass scales. We show that all these
solutions will be tested in future direct detection experiments such as
LUX-Zeplin and Xenon-nT.
