It’s called the Lydian mode. Compared to the “normal” major scale, its 4th degree is raised by a semitone. C Lydian has the notes C D E F# G A B which are the same notes as those in the… G major scale 
Of course, modes are about much more than a bunch of notes in a certain order. You can read more about them here if you are interested, but there’s no need to rush to understand and apply it all right away.