K2-18b is the first super-Earth exoplanet discovered where water is present and with temperatures that could support life as we know it. However, Forbes reported that hydrogen and helium were also found to be abundant in this planet's atmosphere, teaching us that there's no chance this is a similar to Earth.
Modern science is eagerly in search and study for a planet, apart from Earth, with life on it. The ideal 'Earth 2.0' will be an Earth-sized, Earth-mass planet at a similar Earth-Sun distance from a star that's very much like our own. We have yet to find such a world, but even if we do, we must take care that we distinguish between what we think of as biosignatures, like oxygen, produced by life versus that produced by inorganic processes. Many advances are required to reach that stage.
Perhaps the most exciting possibility is to discover a rocky exoplanet with liquid water on its surface and biosignatures in its atmosphere. Over the past few decades, astronomers have uncovered thousands of new exoplanets.
Today, researchers have confirmed over 4,000 exoplanets, with more than 2,500 of those found in the Kepler data. These planets range in size from larger than Jupiter to smaller than Earth. Yet because of the limitations on the size of Kepler and the duration of the mission, the majority of planets are very hot and close to their star, at small angular separations. Some of them are rocky; some are temperate; some have water.
The idea that exoplanet K2-18b is rocky, Earth-like, and has liquid water is absurd. One of the two teams that studied exoplanet K2-18b, which was discovered by Kepler's K2 mission, was able to extract a water signal from the transit data. However, it is water vapor, not liquid water, and only under some (untested) atmospheric scenarios is liquid water on this world even a possibility. K2-18b definitely has an atmosphere, but it's much more "super" than is possible for a rocky planet.