The Belle II experiment is an upgrade of the Belle experiment, and runs at the SuperKEKB accelerator in Tsukuba, Japan. It is expected to collect e+e- collision data corresponding to an integrated luminosity of 50 ab^-1, around 50 times more than its predecessor, Belle. Recently, SuperKEKB has achieved the world’s highest instantaneous luminosity for a colliding-beam accelerator, setting a record of 2.4×10³⁴ cm^-2 s^-1 . Over the running period of 2020, Belle II has collected 57.1 fb^-1 dataset  at the Υ(4S) resonance energy. The physics goals at Belle II have a wide range of areas, including precious test for the Standard Model (SM) and exploration of new physics beyond SM in flavor sector. With enough data samples at Belle in the near future, it is also promising to study the exotic hadrons in the region of new QCD phenomena.

In this talk, I will introduce the topic about exotic hadrons with heavy flavors and show the preliminary results on sensitivity study for searching the tetraquark candidate Z_c(4020)^– in B⁰->D*^–D*⁰K⁺ decays which is performed with Monte Carlo samples at Belle II experiment. And I will also present an outlook for the possible evidence or discovery for Z_c(4020) from B decays with future Belle II data in the mid-long term prospect of the Belle II experiment.