Ultimate X-Men, Vol. 1 #85 (2007)

Sentinels, Part 2
The X-men under Bishop halt the Sentinel attack against the MLF, as well as the MLF attack against city hall. Pyro unexpectedly leaves them to join the MLF, before the X-Men head out on a new mission to track down the source of the new Sentinels.
Release Date: 2007