This dark cinematic backing track is in the key of e minor. The first half of the track includes the following chords:
Em (no5) 0 7 5 x x x
Dadd9 (no5)/E 0 5 4 x x x
C (no5)/E 0 3 2 x x x
A7add11 5 4 0 0 x x
The second half has the following chords:
Em x 7 9 9 8 x
D x 5 7 7 7 x
C x 3 5 5 5 x
A x 0 2 2 2 x
You may have noticed the a major chord, which doesn't naturally belong there, as it contains a c# instead of a c. You should keep that in mind when soloing over that chord.