...Secret Wars (2015) #1...

Secret Wars (2015) #1

The end of the Marvel Universe has arrived. The final incursion is happening. The Marvel Universe is colliding with the Ultimate Universe, and neither will survive!

Learn more here.

What happen with Rachel in Secret Wars, well, we can read this in comicvine:
"Rachel is one of the many that wasn't present on the life raft thus she along with the other survivors have apparently been brainwashed by Doom into believing Battleworld is how things always have been and that Doom is God. Thus Rachel currently resides in the Manhattan Zone of Battleworld."


However we can see two series in which Rachel has a role, these series are Days of Future Past and X-Tinction Agenda, we hope to see her in a regular series of X-Men.

...X-Tinction Agenda...

It has been ten years since the Summers brothers took out Cameron Hodge and end his fascist regime in Genosha, since then Havok and Wolfsbane have toiled and labored to rebuild the island into the proud mutant homeland it once was. But a decade removed from Hodge and his iron rule, their work may all be for naught. A plague has spread across the nation, infecting mutants and threatening the domain known as X-Topia. Faced with an extinction problem, Baroness Rachel Grey had no other solution than to quarantine the island from the rest of the domain, leaving Havok in charge. With the country quarantined and seemingly abandoned by their God and the rest of their fellows X-Men, Havok and Wolfsbane will stop at nothing to save those who are currently trapped on Genosha.

While walking around X-City, Rachel Grey is discussing with Beast about the experiment he is currently developing, more precisely where Beast had time-transplanted some X-Men. In this case, Banshee, Thunderbird and Wolverine just to prove the concept that its possible to bring the dead back to live by taking them from the time before they died. Just then, they are attacked by Havok and his Press Gang in an attempt to capture the mutant healer Triage, the last ray of hope for the mutants of Genosha. The battle is fast and fierce, pitting mutant against mutant, and showing that Havok is taking no chances in reaching his end goal. When Triage is found, Havok pulls the team back to Genosha taking former friends as prisoners along the way. Tests are set up to ensure that Triage's powers will work against the virus. Seeing this as an act of treachery, Rachel Grey prepared to wage war on Genosha.

...Years of Future Past...

Christina "Chrissie" Pryde is the youngest mutant in existence, as fifteen years ago, the Baron of the United Doomstates, President Kelly, created the mutant control act, which put all mutants in internment camps, locking mutants away, creating collars to disable their abilities, and sterilized them. Chrissie goes looking for a chemical, which will disable their collars. Taking the chemical back to her mother, and reuniting with her father, Uncle Erik, and Aunt Rachel, they break out of their camp, and Chrissie uses her newly awakened powers to change into liquid metal and destroy an attacking Sentinel. Meanwhile, President Kelly has hired a team to document footage of mutants killing each other, as soon the American people will vote on whether or not to reform the control act. However, the group of mutants have discovered a virus in the Sentinels to kill the president, and they want Chrissie and Logan's son, Cameron, to save him, believing the image of mutants saving the president will stop the control act once and for all. After a fight against Blob and Mystique, they are attacked by a new form of the Sentinels.

The X-Men and Mystique escaped underground after Cameron killed Blob, They subsequently traveled to Centrum, an underground refuge for mutants. Using a downed Sentinel, it was discovered that President Kelly was fabricating an attack on himself so he could blame mutants. A few moments after this discovery, Sentinels pierced through the ceiling having found Centrum. To counter the assault, Kitty Pryde reached out Centrum's final defense....a giant-sized Lockheed.