Yes, he will be killed by the Didact in the ending sequence of Halo 5 as Agent Locke beholds his death. Halo 6 opens with Agent Locke being stranded in a massive jungle world where the humans have turned into tribals since they were forgotten from the earliest, and darkest days of human colonization.

Halo 6 will introduce armor durability, and different survival and hunting skills be involved to keep your armor working. If your armor starts failing then you will have to find other remedies. You will be capable of finding armor scraps from ancient colonization and military ships that crashed on the planet whilst you learn more and more about the world, and uncover a big mystery in the depths.

Slowly, throughout the game Agent Locke will also reflect on what he has learned about Master Chief, and slowly test his battle abilities will improve as he survives, and either helps or destroys tribal communities, and wildlife. Ultimately, leading him to either become the last hope just as Master Chief was during Halo 3.

Since Agent Locke is not just a fighter, but has some charisma, you will be able to talk with various NPCs in the towns by using a translator module in your armor (that is unlocked through a main story mission) that improves depending on the time and dedication you spend with a specific tribe. Different tribes will offer different possibilities for scavenging and skills that will also affect Locke's appearance.

The game will also feature companions. Perhaps some specific tribals, machines or an AI that will be found throughout the world to help, aid or improve Locke's battle abilities whilst offering an interesting story for Locke to give a damn about as it will offer different approaches to various challenges like bosses.

Whilst the multiplayer will take place either in various arenas, or in an open world. The main character is a custom tribal that is created by the player. Afterwards, players could run through the world by accessing unique multiplayer-only areas and missions, traveling by using a scraped-together vehicle similar to Starcraft's vulture that will run on power cells that can be harvested or charged in various ruins. That vulture can be upgraded to either offer speed, better guns or even appearance (like tribal writings, skulls, animal hides)

The arena, however, will be a restrict place with specific rules, all players will have equal access to all skills and weapons, and it would be about outwitting your enemy by using the map to your advantage.

Whereas the game will be not be made accessible, it will have a brutal difficulty setting, and the default one should feel like a good day on Dark Souls. Agent Locke will also be able to 'boost' his abilities by using different mixes made by tribals, or making his own if he is able to do so. Risking also to become addicted to those substances, that would also punish the player in case they run out, unless they seek treatment.

The game will be marketed everywhere as a chellgning story, with Agent Locke's helmet cracked and a skull painted on it and the jungle background with shadows of the various animals and tribals, but without the 'halo' bit, but only a badass looking '5' at the bottom.

Or maybe, Halo 6 will be a Call of Duty clone with Halo looks.