Observations in the radio band prove the existence of non-thermal components, cosmic rays and magnetic fields, in galaxy clusters. This observational evidence requires a major change in the description of the physical mechanisms in galaxy clusters. The origin of cosmic rays and their interplay with the magnetic fields in the intra-cluster-medium (ICM) is a subject of lively debate in the last decades and constitutes an important science case for the next generation of radio telescopes, including LOFAR and the SKA.
In this talk I will review the most relevant observational facts, based on radio and gamma-ray observations, and the current theoretical understanding of these phenomena. Finally I will discuss future directions in the field. In particular, the LOFAR radio telescope is expected to produce a revolution in the field and I will focus on first results from ongoing projects with this radio telescope.