  Cosmic rays (CRs) propagate in the Milky Way and interact with the
interstellar medium and magnetic fields. These interactions produce emissions
that span the electromagnetic spectrum, and are an invaluable tool for
understanding the intensities and spectra of CRs in distant regions, far beyond
those probed by direct CR measurements. We present updates on the study of CR
properties by combining multi-frequency observations of the interstellar
emission and latest CR direct measurements with propagation models.
