Organic inorganic lead halide perovskite materials have been matured in terms of conversion efficiency reaching the level exceeding those of CIGS and CdTe and approaching those of crystalline Si cells. In addition to high efficiency and high voltage, idiosyncratic merits of perovskite photovoltaic devices are lightweight and flexible body bearing thin and soft absorber film and ability to create a bifacial power generation device by utilizing semi-transparent absorbers, which enable use of the devices in the field where existing Si and CIGS cannot apply without extra cost of fabrication. For industrialization, remaining but serious issues of perovskite PV are reinforcing durability of performance against light and heat and replacement of lead with other environmentally acceptable metals. The former can be overcome by on-going compositional engineering, in particular innovation in developing all-inorganic materials. Further, heat resistance should not necessarily reach the level of Si because a major direction of perovskite PV in commercialization is applications in IoT society where temperature and light intensity environments are benign for perovskite and life of the power device can be as short as IoT devices. However, lead-containing device is not acceptable by the policy of industries rather than actual environmental impacts. In this viewpoint, development of non-lead type new perovskite absorbers is an urgent project for our next step of research. Further, lead-free materials can be invented without using organic cations. This direction of R&D leads to fabrication of non-lead, all inorganic PV devices, and is an important focus of our research to tackle. On the other hand, fundamental study for efficiency enhancement as the challenge to reach SQ limit should be directed to create a single cell capable of the performance approaching to those of GaAs [1]. For lead-based high performance perovskite solar cells, good news is that the device can have high stability, exceeding Si and GaAs, in applications to space satellites, thanks to thin film absorber and intrinsic defect tolerant properties of perovskites. Our recent examinations could reproduce the high stability against electron and proton radiations (published in iScience 2018 [2]) by using high efficiency versions of P3HT-based multi-cation perovskite cells. Needless to say, space industries require lightweight flexible device films loaded on the foldable wings of satellites. In IoT applications, perovskite devices were found to be operated with highest efficiency (>30%) under 200 lux indoor light, which exceeds the highest performance (exceeding amorphous Si) reached by dye-sensitized PV devices (>20%). Towards social implementation, my talk will be concerned with how to focus the strategies and challenges of compositional engineering in the community of perovskite PV.