This article is a brief overview of our recent work on theoretical studies of the interaction of magnetism and superconductivity in nanostructures. General approaches to the analysis of this interaction are discussed and the unified essence of the problem is revealed: the search for new phenomena and effects in such systems. Various aspects of this problem are considered, including proximity effects, solitary superconductivity, and inhomogeneous superconducting states. Approaches based on the properties of the band structure and Fermi surface for ferromagnets and superconductors in contact are considered in the context of predicting possible effects and explaining observed phenomena. The possibilities of further research in this area are discussed in order to expand our understanding of the physics of magnetic superconductors and develop new technologies based on them.