X-Men Origins: Wolverine (2009)
Wade Wilson, also known as Deadpool is a wisecracking mercenary with lethal swordsmanship skill and athleticism.
Wade was diagnosed with inoperable brain cancer and signed up to join the Weapon X program which gave him a healing factor similar to Wolverine. It resulted in his mind is in a constant state of disarray; the cancer cells are repeatedly destroyed but regenerated in a never-ending loop.
Deadpool 2 (2018), X-Force (2019)