The seminar will address a range of key topics: the nature and origin of diffuse X-ray emission in the interstellar medium (ISM), supernova remnants (SNRs) as sources of energetic particles and feedback into the ISM, and the population and evolution of compact stellar remnants like white dwarfs, neutron stars, and black holes. A central theme will be the synergy of X-ray data with observations across the electromagnetic spectrum, including optical, radio, infrared, and gamma-ray bands.