Hybrid beamforming for massive MIMO is a promising approach to reduce hardware cost and training overhead. This survey discusses various hybrid beamforming structures, categorizing them based on the required channel state information (CSI): instantaneous or average. Hybrid beamforming combines analog and digital processing, with analog components handling large-scale antenna arrays and digital components managing lower-dimensional processing. The paper highlights the design aspects for millimeter-wave frequencies, where large array gains are needed to overcome high path loss. It also discusses the trade-offs between complexity and performance, and the impact of RF hardware imperfections on system efficiency. The survey covers different hybrid beamforming structures, including those based on instantaneous and average CSI, as well as those with selection stages. It also addresses the challenges of wideband systems and the importance of reduced-dimensional CSI for massive MIMO. The paper concludes that hybrid beamforming is essential for future 5G systems, offering a balance between cost, energy efficiency, and performance.Hybrid beamforming for massive MIMO is a promising approach to reduce hardware cost and training overhead. This survey discusses various hybrid beamforming structures, categorizing them based on the required channel state information (CSI): instantaneous or average. Hybrid beamforming combines analog and digital processing, with analog components handling large-scale antenna arrays and digital components managing lower-dimensional processing. The paper highlights the design aspects for millimeter-wave frequencies, where large array gains are needed to overcome high path loss. It also discusses the trade-offs between complexity and performance, and the impact of RF hardware imperfections on system efficiency. The survey covers different hybrid beamforming structures, including those based on instantaneous and average CSI, as well as those with selection stages. It also addresses the challenges of wideband systems and the importance of reduced-dimensional CSI for massive MIMO. The paper concludes that hybrid beamforming is essential for future 5G systems, offering a balance between cost, energy efficiency, and performance.