At the beginning of Outbreak, American scientists visit a camp in the middle of a jungle to assess a disease and take blood samples. There were also American soldiers at the camp. Was this a depiction of a real-world war? If so, which?
The bulk of Outbreak takes in Zaire, which fell apart not long after the movie’s release in the first Congo War. American military advisors went to Rwanda in the aftermath of that country’s genocide, and Le Monde reported some of those advisors did operate in Zaire.
I should note, Rwanda didn’t officially invade Zaire until 1996 in their counteroffensive against the génocidaires who had fled Rwanda when they lost, but the CIA had run paramilitary operations in Zaire going back to the 60s. It’s plausible the CIA had paramilitary operations in Zaire in 1995, especially with the growing threat to Rwanda from militants operating out of refuge camps on the Zaire’s eastern border.
The US did officially send the military into eastern Congo to help with relief efforts in 1996.
So I wouldn’t go so far as to say that Outbreak was based on any specific conflict, more that it drew from what was happening around that time. The Congo’s been embroiled in near-perpetual conflict since it's independence from Belgium in the 60s. Depicting an armed conflict or war in that region, tragically, doesn’t strain the imagination.
Timeline of Cental Africa up to 1990 from the Guardian https://www.theguardian.com/world/1999/mar/03/uganda.gwyntopham
Article from the US Department of State historian on CIA activities in the Congo https://www.cia.gov/library/center-for-the-study-of-intelligence/csi-publications/csi-studies/studies/vol-58-no-3/pdfs-vol-58-no-3/Robarge-FRUS%20and%20the%20US%20in%20Congo-1960-68-12Sep2014.pdf