There are lots of Halo movies and shows:
Down below there is the list of shows and movies some are very good and some are not so good.
Halo legends is a cartoon based on theories of the halo universe including the forerunner the other alien race such as the flood and more.
Halo forward unto dawn:
People say this movie is terrible but the story of the movie shows the marine program and how Master Chief saves children from Reach saving a general that is to be known as a commander as he goes through ranks.
This is the story of Spartan Locke and how him and his team go to the last Halo Ring and destroy it without electronics because an alien race can only see electricity as that is what they eat. The soldiers have low oxygen, low food and are almost stranded on the ring and are blown up.