Nonequilibrium Kondo problem is one of long standing problems in condensed matter physics. For this reason, all of the experimental observations for the tunneling conductance of various Kondo-involved mesoscopic systems are not properly explained. In this talk, I discuss the transport of two different types of entangled Kondo singlet in steady-state nonequilibrium. One of them produces zero-bias peak and the other is responsible for two side peaks in tunneling conductance.  The two side peaks are the manifestation of Kondo effect at steady-state nonequilibrium.  I will introduce the theoretical method that gives the on-site Green’s function for the two-reservoir Anderson impurity model under bias and tunneling conductance. I will show that the antisymmetric combination of the left and the right Kondo singlet provides the tunneling eigenstates for two side peaks, while the symmetric combination corresponds to the zero-bias peak. Finally, I reproduce the dI/dV line shapes of various mesoscopic Kondo systems such as quantum dot single-electron transistor, quantum point contact, and adsorbed magnetized atom on a metallic substrate. I also discuss the line shapes of multilayer graphene and high-Tc superconductors in terms of the extended version of the two-reservoir Anderson impurity model.