The measurement of the Cosmic Microwave Background has played a critical role in establishing the standard Lambda CDM cosmology of today. While this standard cosmology has been very successful, there are still unresolved questions which can be solved by introducing the theory of inflation. Remarkably, the theory of inflation can be tested by measuring CMB B-modes. There is currently a world-wide competition to measure this signal first. Measurements from space have an advantage in terms of sky coverage and availability of observation bands, and this is particularly attractive for the search for primordial B-modes. There have been a number of satellite proposals to probe the inflationary B-mode signal, but none has been selected until last year. LiteBIRD is selected as the second strategic large-class mission at JAXA and aims for a sensitivity of the tensor-to-scalar ratio below 10^-3. This sensitivity can probe at least an order of magnitude deeper than that of ESA's Planck. In this talk, we will review the current state of cosmology with the measurement of CMB polarization. We introduce our effort on LiteBIRD and the prospective role of IPMU. Finally, we will discuss the future of these studies beyond LiteBIRD.