Out of Shadow
From Halopedia, the Halo wiki
Out of Shadow is a song included in the Halo 3: Original Soundtrack. It includes the songs Out of Shadow and Into Light, and plays during the level Tsavo Highway and The Ark. It runs for 4 minutes and 30 seconds. In Halo 2, the first part of this song was played when you first encounter Jackal Snipers, and the second part of this song was heard during a battle with Shadows on the level Outskirts, hence the name.
The song is a remake of Mombasa Suite from Halo 2. Listening to both tracks, similarities can be quickly found.