The magneto-ionic medium in the Milky Way

One way in which the Canadian Galactic Plane Survey has made an important contribution to the understanding of the Galactic interstellar medium is through its polarization surveys. Investigation of these data has enabled a big step in the study of magnetic fields in the interstellar medium and a range of discrete, extended, interstellar objects. In this review, I will discuss the role that the magnetic field plays in the interstellar medium, summarizing the ways in which magnetic field interacts with the other components in the Milky Way. Magnetic fields in the Galactic halo are discussed, and an outlook to a number of successor surveys of the polarized CGPS in the near future is given.