Abstract: The Background Imaging of Cosmic Extragalactic Polarization (BICEP) in its second data release in March 17- 2014 announced the indirect detection of primordial gravitational wave by using the CMB - B mode polarization. In this talk I will review the main results of BICEP2, reviewing their method of the subtraction of the foreground signals due to dust, synchrotron radiation and CMB lensing. Then I will summarize the main results and the cosmological implication. Also I will indicate the existence of the tension between Planck and BICEP2 results on their prediction for anisotropy of CMB perturbations in large angular scales, discussing the consequences and future prospects.