This Special Issue aims to set itself at the cutting edge of the most recent advances in the intertwined ties of cosmology with other fields at all relevant scales from mutually fertilizing theoretical, phenomenological, and experimental perspectives. Topics include, but are not limited to, the following: cosmological models; inflationary cosmology; big bang; bounce cosmology; cosmic string/string theory; quantum cosmology; observational cosmology; ΛCDM cosmology; dark matter and dark energy; axion cosmology; cosmic acceleration; cosmological constants; cosmological perturbation theory; cosmic microwave background (CMB); Hubble's law/constants; machine learning and cosmology; and the large-scale structure of the universe. It is our pleasure that this Special Issue on various recent topics in modern cosmology and related fundamental physics is useful for future studies.