Mount Elbrus, in the Caucasus region of Russia, 65 km southwest from Kislovodsk, is a major, isolated volcano in the heart of a continent-continent collision zone. It is not normal for volcanoes to form in such settings (see e.g. this question). How did Elbrus form? I have not been able to find any good resources online (any links would be welcome). Please also mention other examples of similar volcanoes if you are aware of them.
It's a fairly dense analysis, but this paper seems to have your answer: Young Silicic Magmatism of the Greater Caucasus, Russia, with implication for its delamination origin based on zircon petrochronology and thermomechanical modeling. It's also a cited in the paper mentioned in the comment by klanomath, though the figures aren't as appealing.
Thermomechanical modeling bolsters the existing idea that magmatism in the Greater Caucasus is the result of the breakoff of a subducted slab at ~5 Ma in what would be an otherwise amagmatic post-collisional environment. Large volumes of silicic magmas were rapidly produced by the intrusion of hot asthenosphere into a lithospheric window left behind by the foundered slab. This material underwent decompression melting and produced silicic magmas by heating and melting the crust. Further silicic magmas were produced by the detachment and melting of buoyant material from the foundering slab. Sometime after this initial melting event, crustal thickening eclogitized the lower crust of the continent formerly attached to the subducting slab, causing it to delaminate along with the underlying continental lithosphere over a region at least 200 km across. This produced a large surge of melting in the upper mantle and accompanying mafic volcanism, possibly explaining the existing high volcanic field in the Lesser Caucasus.