Can someone tell me where or what anime it's these two characters from? I was just listen some music on my YouTube, but for some reason I wanted to know from where are the characters of the illustration, or something.

I tried to investigate in various sites, but I failed without success.

(Also, if you want the video, so here go: https://m.youtube.com/watch?v=FtUOPCEMKQI&pp=ygUGc2hpbWF10gcJCbIJAYcqIYzv ).