Explore the synergy and competition between X-ray and microwave cosmology in this lecture by Rashid A. Sunyaev. Delve into the cosmic microwave background radiation and its interactions with hot electrons in the universe. Learn about the latest developments in X-ray and microwave telescopes, including ground-based instruments like SPT and ACT. Discover the physics behind Comptonization and its effects on CMB observations. Examine the role of galaxy clusters in cosmological studies and the capabilities of advanced instruments such as ALMA. Gain insights into upcoming space missions like SRG and eRosita, and their potential contributions to our understanding of the cosmos. Engage with cutting-edge research in astrophysics and cosmology through this comprehensive presentation.