Until 2003, Godspeed You! Black Emperor had a cellist, Norsola Johnson, which I think gave them a very unique sound especially in the album linked (Lift your skinny fists like antennas to heaven). However, while they do have a violin in the new albums, the sound is quite different.

What other bands use cello? This patch of sky is one (and fantastic), but they disbanded in 2019. Gregor Samsa used to have one but they swapped to violin as well (and their style was very different anyway). Three Silver MtZion doesn’t have their cellist anymore as well.