The article reviews the advancements in graphene plasmonics, focusing on its unique electrical and optical properties, tunability, long-lived collective excitation, and extreme light confinement. The authors discuss the basic properties of graphene plasmons, including their energy dispersion, localization, propagation, plasmon-phonon hybridization, lifetimes, and damping pathways. They highlight the potential applications of graphene plasmonics in the terahertz to mid-infrared regime, such as modulators, notch filters, polarizers, mid-infrared photodetectors, and vibrational spectroscopy. The review also explores the development of scanning near-field optical microscopy (SNOM) for imaging plasmons and the coupling of plasmons with phonons, which can enhance the optoelectronic response of graphene. Additionally, the article discusses the use of graphene metamaterials for active devices, including tunable filters, linear polarizers, and transformation optics. The potential of graphene plasmons in mid-infrared vibrational spectroscopy is also examined, emphasizing their ability to enhance the infrared activity of phonons.The article reviews the advancements in graphene plasmonics, focusing on its unique electrical and optical properties, tunability, long-lived collective excitation, and extreme light confinement. The authors discuss the basic properties of graphene plasmons, including their energy dispersion, localization, propagation, plasmon-phonon hybridization, lifetimes, and damping pathways. They highlight the potential applications of graphene plasmonics in the terahertz to mid-infrared regime, such as modulators, notch filters, polarizers, mid-infrared photodetectors, and vibrational spectroscopy. The review also explores the development of scanning near-field optical microscopy (SNOM) for imaging plasmons and the coupling of plasmons with phonons, which can enhance the optoelectronic response of graphene. Additionally, the article discusses the use of graphene metamaterials for active devices, including tunable filters, linear polarizers, and transformation optics. The potential of graphene plasmons in mid-infrared vibrational spectroscopy is also examined, emphasizing their ability to enhance the infrared activity of phonons.