The third generation (3G) of mobile communications has been successfully standardized and implemented throughout the world. International Mobile Telecommunications-2000 (IMT-2000) technology is a representative realization of 3G technology. Currently IMT-2000 is evolving to a next generation standard named IMT-Advanced. Major milestone technologies that lead 3G in to the fourth generation (4G) standards include Mobile Worldwide Interoperability for Microwave Access (WiMAX) and Long Term Evolution (LTE). Mobile WiMAX and LTE technology have different origins, but there are similarities in their path of evolution. In this paper, a comparison of evolution history and future expectations are discussed on Mobile WiMAX and LTE. In addition, the evolution of Wireless Local Area Network (WLAN) as a popular inter-operating technology with Mobile WiMAX and LTE is also discussed.