Actually, there are many differences. K-pop is actually not a genre of music, but an industry. Specifically, the majority of the Korean music industry is labeled as “K-pop” although it really may not be 'pop' music. Pop however, like I said, is not just “pop” but many genres. BTS, a well known Korean boy group, has songs with different genres, so they can be just labeled as one genre. Their songs, “Save me”, and “Idol” are pop. Their song “Mic Drop” might just be Hip-Hop, and many others have EDM, indie, jazz, rock and other elements in them that don't simply make them pop.