Well let's think about this for a minute. The Halo and Destiny franchises both have very similar enimies...Vex = Forerunners, Cabal = Brutes, Fallen = Covenant (minus Prophets of course, which is why they may be called the Fallen), Hive = Flood. Obviously there are very similar fighting styles in both games, as well as armor types/styles, weapon types, shields, etc.. Halo 5 is called Guardians, and also in a teaser trailer for Halo 5, we see the Master Chief wearing what appears to be a hunter's cloak -- strange choice for a guy who already has an amazing suit of armor. In that same video a massive construct emerges from a sandy desert and is large enough to be compared to Destiny's Traveler. In a seperate trailer, there is a group of spartans who are searching for the Master Chief and collaborating with the covenant and the Arbiter, and the group of spartans identifies themselves as "Hunters." Also, it is pretty clear that Ghosts in destiny and 343 Guilty Spark share more than a passing resemblence. My theory is that the events of the Halo franchise far predate the events of Destiny, but happen in the same universe and are linked through time travel. We have already seen with Atheon and the Vex in Destiny that time travel is more than possible -- I truly believe there is a link between the Halo franchise and Destiny that has yet to be revealed.

You, ah, misspelled "guardians".