Exotic hadronic states beyond the conventional quark model (called charmoniumlike/bottomoniumlike states or XYZ particles) have been searched for and many candidates were proposed including glueballs, hybrids, multi-quark states, hadron molecules, etc. Dramatic progress was made in the study of the exotic states after the running of the two B -factories, i.e., Belle at KEK and BaBar at SLAC. In my review report, I present the most recent results on the study of the XYZ states from the BESIII, Belle, BaBar, LHCb, CMS experiments, etc., including (1) X states: the observation of the X(3872) in e + e − → γX (3872) at around 4.26 GeV; searches for the X b state; (2) Y states including the updated results for the Y (4008), Y (4260), Y (4360), Y (4660), etc; (3) Z states including the observations of the Z (4430), Z 1 (4050), Z 2 (4250), Z c (3900), Z c (4020), Z c (4200); the evidence for the Z c (4050) ± → π ± ψ (2 S ); search for the Z cs in e + e − → K + K − J/ψ .