Venus is uninhabitable for humans yet from a distance, using statistical wobbles, a Venus-like planet and an Earth-like planet are very similar.
While the Earth has oceans of water and relatively moderate temperatures, Venus has no liquid
water and exists in a runaway greenhouse scenario where the levels of carbon dioxide are so high that the atmosphere traps all the heat. The planet is torrid but it is 95 percent the size of Earth. Right now, size is what astronomers are looking for when searching for exoplanets but size alone is not a distinguishing characteristic when sorting for a habitable one.