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Energetic feedback from stars and supermassive black holes (SMBHs) is key ingredient in the formation and evolution of galaxies and clusters, as shown by state-of-the-art cosmological simulations. However, predictive powers of these simulations are limited by the important but often neglected microphysics -- physical processes that are unresolvable and not captured by purely hydrodynamic simulations. One of such examples is cosmic rays (CRs). In this talk, I will discuss how CRs could influence feedback processes across different mass scales, including AGN feedback in galaxy clusters, Fermi bubbles within our Milky Way Galaxy, and galactic winds in dwarf galaxies. In particular, I will discuss how the detailed microscopic processes of CR transport could have dramatic impacts on the macroscopic properties of galaxies and clusters.