Marvel's House of X / Powers of X event series has totally redefined the X-Men franchise and mythos, and writer Jonathan Hickman has introduced some bold new vision of what that brave new world looks like. One of the biggest and most controversial changes that Hickman has made to X-Men lore is introducing a resurrection that makes the X-Men and any other mutant basically immortal. Like any fantastical comic book device, the introduction is one thing - but the larger explanation is a whole other matter. Hickman recently opened up in an interview about what X-Men's new mutant resurrection process is all about - and when we'll learn more about it.
Here's what Jonathan Hickman had to say to AIPT about Marvel's new mutant resurrection process, and when we'll get to know some of the finer details about it: "...the issue you’re looking for is (I think) X-Men #7 (it’s the one with Apocalypse and Nightcrawler on the cover). This will cover all the life-death-resurrection-soul questions."
Indeed, Marvel fans have had quite a few questions about this Resurrection process since Hickman introduced it. The process itself involves a collection of (mostly obscure) X-Men characters who have rebranded "The Five." By combining their powers, this group is able to grow new bodies for dead mutants in special eggs using a DNA archive of all mutants, complete with the ability to replicate a mutant's powers. Once a body is grown and full re-powered, Charles Xavier uses the combination of Cerebro and his own psychic archive of "downloaded" mutant minds to return the dead mutant's psyche (and arguably "soul") back to the empty shell of a body.
Naturally this two-step process has inspired all sorts of pertinent questions, such why The Five and/or Xavier don't "correct" flaws in some mutants (like making Cyclops' Optic Blasts voluntary and controllable); or how certain mutant bodies get restored in full (like Wolverine's Adamantium). That's not to mention the massive philosophical and/or religious quandaries that indeed come with such a process.
...That's all to say: X-Men #7 is definitely not an issue to miss!
Marvel is currently relaunching the X-Men books, with Hickman's X-Men #1 now on sale.