DEATH
Using thoughts and notes from the recently murdered Moira MacTaggert, the X-Men's resident scientist, Beast, claimed to have found the cure for the Legacy Virus. Unfortunately, it could only be made airborne with the death of its first user. Rather than wait for a safer version and allow others to die as Illyana had, Colossus injected himself with the cure. By using his powers and sacrificing himself, Colossus enabled the release of an airborne cure, effectively eradicating the disease. His body was cremated, and Shadowcat took his ashes back to Russia to be scattered on his native soil.[46] [ UNCANNY X-MEN 390 ]
https://viewcomiconline.com/uncanny-x-men-1963-issue-390/RETURN
Nearly two years later, it was brought to the attention of the X-Men that a medical company, entitled Benetech, had developed a mutant cure. After gaining a sample of the cure, Dr. Henry (Beast) McCoy discovered a string of DNA hidden deep within the recesses of the formula. After matching the DNA, Beast and the other X-Men set out to investigate the truth behind Benetech.
During their infiltration, they discovered that Ord, an alien from the Breakworld, was responsible for the means with which the company was able to develop the cure. While the team was separated, Kitty descended into a hidden complex beneath the Benetech building and was able to unlock the true secret behind the cure: shortly after Peter's self-sacrificing death, Ord had captured his body and left a duplicate that the X-Men had cremated.[47] [ ASTONISHING X-MEN 4, 2004 ]
After reviving him, Ord had used the Legacy Virus cure in Peter's bloodstream to develop his mutant cure. After unknowingly releasing Peter from his cell, Kitty rejoined him with the X-Men. Together they subdued Ord as he tried to escape Earth. Since reuniting with his friends, Peter has returned to fight with the X-Men, and he and Kitty were able to resume their romantic relationship.[47] [ ASTONISHING X-MEN 4, 2004 ]
https://viewcomiconline.com/astonishing-x-men-2004-issue-4/
