The complexity of RF front-end (RFFE) modules of wireless devices has increased dramatically over the past decade. In order to meet the demands for future mobile communications, RFFEs will need to enable multiband for global roaming, and multi-mode to support multiple cellular modes, incorporate beamforming antennas, and operate at mm-wave frequencies. To this end, this article presents a summary of the recent progress in RF substrate technologies, waveguide architectures and multi-band design techniques for 5G RFFE modules, and summarizes the present and future challenges in RFFE module design.