It's a pairing that appears in a animated series called Alien Stage on YouTube by the channel VIVINOS (the director of the series). Basically you can sum up their relationship with "Doomed Yaoi"
There's also doomed Yuri with another pair, Mizi and Sua, except they're both in love with each other, while IvanTill fans can only grief in despair with IvanTill because it's a one-sided love, and the other one loves Mizi, one of the girls I just mentioned
You can check it out if you've braced your heart for the pain, but nonetheless it's a great series with amazing plot and character design/writing, topping it off with some hella good music
...after marinating this for 10 weeks... THIS IS WHAT I GET I WHAT IN THE ACTUAL FUCK IS THAT????