Dr. Yerong Xu currently is a postdoctoral fellow at Saint Mary’s University (Canada) and is going to join the Institute of Space Sciences (Spain) as a junior postdoctoral fellow in October. He received his Ph.D. from the University of Palermo and the National Institute of Astrophysics of Italy, in 2024, M.S. from the University of Chicago in 2020, and B.S. from Fudan University in 2019. He was a European Space Agency (ESA) archival research visitor in 2022 and an Erasmus+ visitor at Massachusetts Institute of Technology in 2023. His research focuses on the X-ray view of active galactic nuclei (AGN) and the co-evolution of supermassive black holes and their host galaxies.Ultra-fast outflows (UFOs) are an extreme subclass of winds in active galactic nuclei (AGN), characterized by mildly relativistic speeds and high ionization states. They are considered one of the most promising candidates to drive AGN feedback, potentially shaping the co-evolution of supermassive black holes (SMBHs) and their host galaxies. However, the underlying processes of UFOs driving AGN feedback remain unclear, particularly concerning their acceleration mechanisms and wind structures. In this talk, I will review recent progress in UFO studies, and present new insights from the performance verification (PV) observation of the recently launched high-resolution X-ray mission XRISM, focusing on the prototype UFO source, PDS 456.