I just discovered this awesome band today. This is the opening song of the anime Black Cover, which I have yet to watch.
Distant Future (ハルかミライ）by Kankaku Piero (感覚ピエロ)
I stumbled upon them upon watching the Japanese drama, ゆとりですがなにか (Yutori Desu ga Nani ka lit. “We’re Millenials. Got a problem?”) to which they also did the opening theme.
To You Someday, Sir (拝啓, いつかの君へ) by Kankaku Piero (感覚ピエロ)