  Over the past few decades, wireless communication has witnessed remarkable
growth, experiencing several transformative changes. This article aims to
provide a comprehensive overview of wireless communication technologies, from
the foundations to the recent wireless advances. Specifically, we take a
neutral look at the state-of-the-art technologies for 5G and the ongoing
evolutions towards 6G, reviewing the recommendations of the International
Mobile Communication vision for 2030 (IMT-2030). We first highlight specific
features of IMT 2030, including three IMT-2020 extensions (URLLC+, eMBB+, and
mMTC+) and three new innovations (Ubiquitous connectivity and integrating the
new capabilities of sensing & AI with communication functionality). Then, we
delve into three major challenges in implementing 6G, along with global
standardization efforts. Besides, a proof of concept is provided by
demonstrating terahertz (THz) signal transmission using Orbital Angular
Momentum (OAM) multiplexing, which is one of the potential candidates for 6G
and beyond. To inspire further potential research, we conclude by identifying
research opportunities and future visions on IMT-2030 recommendations.
