Unlike other bears, which used their caves mainly for hibernation, Cave Bears spent much more time in their caves. It's not uncommon to find the fossilized skeletal remains of several cave bear families from different time periods in the same cave.
This dependency on caves may have been what did the Ursa spelaeus in, as it was one of the first Ice Age species to go extinct. While the brown bear was more flexible in its habitat, Cave Bears had a difficult time hibernating outside of caves - a shelter that ancient humans were also drawn to. This dwindling supply of a very specialized habitat, along with a specific diet vulnerable to climate change, precipitated the decline of the Ursus spelaeus.
While the overlap between our ancestors and the Cave Bear may have been brief before they disappeared, it appears as though they were not forgotten. Evidence of Cave Bear remains being used for rituals and possibly worship by Neanderthals has been found in several caves throughout Europe. Our ancestors likely had to interact frequently with the remains of Cave Bears as they took over habitation of caves that provided shelter for these bears for up to 100,000 years.