Recent developments in Radio Frequency Power Amplifiers (RF PAs) (2016–2025) cover a wide range of semiconductor technologies and architectures. GaN HEMT designs prevail in high-power efforts, frequently exceeding 35–40 dBm output with PAE between 30% and 60%. High linearity over broad bands (e.g., gain flatness ±0.8 dB) is achieved by GaAs-based PAs (pHEMT or HBT) at moderate power (20–26 dBm). CMOS PAs prioritize integration and linearity at reduced power (Psat <30 dBm). Continuous-mode (Class-J) and harmonic compensation networks, outphasing/transmit combining, Doherty, and balanced architectures are the prominent ones. Predistortion and device-level linearization (derivative superposition, diode predistorter, adaptive bias) are repeated for enhancing ACLR and EVM. Trade-offs are seen between peak efficiency and linearity: e.g., matching for peak PAE (~36%) resulted in 37.5 dBm out, while retuning for linearity improved IMD3 slightly at ~33% PAE. DPD is routinely employed to increase linearity under complex modulations, achieving ~16–17 dB ACLR improvement at mmWave frequencies. In summary, GaN PAs excel in raw power and efficiency, GaAs HBT/pHEMT PAs prioritize broadband flat gain and linearity, and CMOS designs emphasize integration and low-voltage linear performance. The emerging directions indicate hybrid architectures and novel bias or signal processing to overcome the classic efficiency-linearity trade-off in modern 5G/Wi-Fi transmitters.