According to the search results, John Wicks wife, Helen, died of a terminal illness before the first movie. Although the franchise doesnt explicitly identify the illness, Helen was sick for a long time before her death. Her death has an overarching influence on John Wicks road to revenge and his strained desire to leave the hitman business behind again. Helens death is the reason John Wick did one last job for Viggo Tarasov in order to retire, and it was her death that would incite his vengeful return to the criminal underworld. Helens two major gifts to John, the vintage car and the beagle Daisy, are the catalysts for his return to his career of violence and killing. Helen has appeared in every installment of the franchise through flashbacks and photographs, being portrayed by Bridget Moynahan.