The Kepler mission has a list of "candidate exoplanets." Kepler has made thousands of likely exoplanet discoveries, but in order for each planet to be considered "confirmed", its existence has to be verified using other instruments, a process that takes time.
As the SETI and Kepler team as well as other researchers across the world sift through the Kepler mission's immense collection of data, it's possible that some candidates will prove to be "false positives" - findings that appear to be exoplanets at first, but later turn out to be the result of other cosmic phenomena.
However, it's very likely that the vast majority of the Kepler exoplanet candidates, especially those in multi-planet systems, are real exoplanets.
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The Kepler Mission