Paramount+'s Halo TV series appears to be set towards the end of the Human-Covenant War, and if it follows the same timeline as the games it should be set in the year 2552. The Halo Xbox games introduced players to a galaxy at war - where the human race had come under sustained attack by a mysterious alien Covenant, who were set on nothing less than the complete extermination of humanity. Earth's only champions are the Spartans, genetically-engineered super-soldiers who wear powerful Mjolnir armor, making them a match for the Covenant in ground battles.
In the game timeline, the Great War between humanity and the Covenant began in 2525. The Covenant discovered a human ship that had dropped out of slipspace due to a malfunction, and after an encounter on the planet Harvest the Covenant's Prophets declared humans an affront to their gods. Thus began a relentless crusade, with Earth's UNSC desperately battling against the invaders. The war lasted over 25 years, with countless colony worlds "glassed" - obliterated by plasma bombardments from space that fused sand into a hard silicate. It came to a head in 2552, when the Covenant destroyed the major UNSC military base on Reach; only one vessel escaped Reach, jumping through slipspace to the recently-discovered coordinates of the first Halo Ring.
It's unclear how closely Paramount+'s Halo TV series will align with the events of the games. The focus will inevitably lie upon the discovery (and subsequent use) of the Halo Rings, though, meaning Halo's events will likely take place in the final year of the Human-Covenant War, in the year 2552, assuming the timeline hasn't been changed.
Halo's Human vs Covenant War Timeline Overview
In the timeline of the Halo games, 2552 is a year of unprecedented conflict. The Fall of Reach is essentially the beginning of the final Covenant advance, with the aliens even launching a precision strike against Earth - a planet whose coordinates had been kept from them for over 25 years. Meanwhile, the discovery of the Halo Rings unleashed the threat of the Flood, while the possibility of the Rings being used meant the galaxy came close to being sterilized of all life. All this coincided with a period in which human knowledge - both of the Covenant and of their own prehistory - expanded at a dramatic rate. While it's reasonable to assume Paramount+'s Halo TV series will tell a different version of events, the fact remains the story potential here is massive.
Hopefully the Halo TV series will be a success. The wider Halo timeline has been explored by a range of novels, and it would be good to see more of the galaxy's past - and the Human-Covenant War - brought to life on the small screen as well. Should Halo prove popular, Paramount+ could potentially launch spinoffs exploring the timeline in greater detail.