Noob question regarding harmonization

[maihasegawa]

Not sure if it's okay to post a musical theory question here, but I actually don't know other places to get helps for music creation. Sorry if I shouldn't post it here and please let me know if I should move or delete the thread.

When transcribing some music, I sometimes encounter notes that are totally outside of the chord, e.g. in the track below, the "A" doesn't belong to any notes of the Cmaj7 chord. Is this the case when we call a note out of chord ? If it is, why is this legit (and actually sounds amazing) ?

[Audiobusters]

maihasegawa wrote: ↑Sun May 15, 2022 6:19 pmI s...

[maihasegawa]

Audiobusters wrote: ↑Mon May 16, 2022 3:10 am m...

[DantheMan17]

TranceCrafter wrote: ↑Sun May 15, 2022 6:27 pm ...

[craig bradley]

I would strongly recommend learning a bit of th...