what type of music is this song?
 

the song comes from kpop.
the music in the beginning reminds me of 'big band'.
when they start singing its no longer 'big band' but something else.

youtube.com/watch?v=tw7oe2FD0dU

i know i can put it under the category of Jazz in general. but what would be the Sub genre?

Smooth jazz. As you noticed, it starts differently, with some neo-swing drums and piano, but basically it's just vocal smooth jazz with a tiny bit of a lounge element.

i dont like kpop music