Can electromagnetic waves e.g. light be deflected by a magnetic field?
If you mean: "can a light beam be deflected by a magnet" like an electron beam gets deflected by an electric field - then the short answer is no.
If you look at how the magnetic field of the light wave is oriented (transverse), you'll see that it behaves in an external magnetic field much like a magnetic dipole does - by rotating.
This is called the Faraday effect.
Exploited in electrical polarizers.
Photons do feel the EM interaction though, and can, in principle, scatter from other photons.
However, afaik, it has yet to be observed.
You need a material medium for this interaction. It doesn't happen in free space.
The description was a bit glib.
No examples of free-field deflections available.
Separate names with a comma.