Here is a summary of Warren's story arc in that story:
-Warren sinks into depression losing faith in co-existing with humans.
-Apocalypse takes advantage of this and manipulates him into being his final horseman.
-Warren causes tons of death and destruction across New York under the behest of Apocalypse.
-Warren's old friends try to reach him and after ignoring their pleas his friendship with the First Class finally breaks him free of Apocalypse's influence and he turns on him.
-Warren is welcomed back to X-Factor but declines due to what he has done.
Doesn't that sound familiar?
Here is a more in-depth comparison.
http://stay-tuned-true-believers.tu.../x-men-apocalypse-compared-to-the-comic-books