I'm staggered that I never wrote a post about this awesome song sooner:
It's "Hold My Hand" by Jess Glynne. Released in March 2015, it is the third single from the debut studio album, I Cry When I Laugh. I listened to this song countless times in 2015, as it helped with cope with the events of that year; while I don't listen to it as much nowadays, I still love it.
While "Hold My Hand" has not been featured previously in Air Nice-to-Livelands, Glynne herself has, appearing in the following posts: (1), (2), (3), (4). I listen to a Glynne song most days, as her music generally puts me in a good mood.