"Gorillas in the Mist" proves to be a truly valuable movie, effectively showcasing Dian Fossey's often remarkable efforts. Her ability to become part of the mountain gorilla group leads to some exceptional footage depicting gorillas in their natural environment; it’s hard to tell at times whether what you are seeing is achieved through visual effects or if it’s simply real gorillas. It appears that her increasingly all-encompassing dedication eventually overshadows other areas of her existence—she even starts calling the gorillas and their mountain home “hers”—and she chooses to remain on the mountain with them, studying them, foregoing a developing relationship with photographer Bob Campbell. Dian Fossey gained acknowledgement because of what she did, and the film concludes by noting that the gorilla population is still growing, reflecting the lasting impact of her achievements; however, this positive note is paired with the unsettling reality that the circumstances surrounding her death are still unknown.

Source on TMDB