Exoplanets with relatively clear atmospheres are prime targets for detailed studies of chemical compositions and abundances in their atmospheres, which could be hopefully connected to their formation and evolution history. Alkali metals have long been suggested to exhibit broad wings due to pressure broadening, but most of the alkali detections only show very narrow absorption cores, probably because of the presence of clouds. In a recent work on the super-Neptune WASP-127b, we simultaneously detected Na, K, and Li in its atmosphere. This is not only the first time that both Na and K exhibit strong pressure-broadened wings, but also the first time that Li is detected in an exoplanet. I will review this discovery and discuss in general the characterization of alkali metals in exoplanet atmospheres.