Dante speaks with Guido in the eighth trench of the eighth circle of hell. Guido gave false advice to the pope. The pope absolved Guido in advance of his sins, but he still ended up in hell because he did not actually repent his sins when he was supposedly absolved.
The timeline below shows where the character Guido da Montefeltro appears in Inferno. The colored dots and icons indicate which themes are associated with that appearance.