Basically the plot revolved around a massive war across galaxies of humans vs ai/human hybrids. Think all sorts of futuristic tech, tanks, ships, planes, AI, etc. I'll paste an except from wikipedia below:
"In the far future the galaxy is ruled by a benevolent central government of humans and artificially intelligent machines called the Core. The Core's technological and economic triumphs have allowed humanity to colonize most of the milky way and enjoy a golden age of peace and prosperity. However, the peace is shattered by a technological breakthrough dubbed patterning, which allows the consciousness of a living human being to be reliably transferred into a machine, thereby granting a theoretically indefinite lifespan safe from disease, ageing, and pain.
Following a mandate imposed by the Core requiring all humans undergo patterning as a public health measure, a rebellion ensued among those who refused to abandon their natural bodies to join the Core's transition to an entirely machine society. Fleeing the developed Core worlds, the rebels established themselves in the remote rimward regions of the galaxy, coming to be known as the Arm. As hostilities escalated, the Core began duplicating their greatest military minds to mass-produce sentient war machines, and the Arm countered this buildup with a campaign of cloning bioengineered pilots for theirs; a war that would last four thousand years began."
by AdIllustrious4209