From CW News:

The appointment of Cardinal Luis Tagle as prefect of the Congregation for Evangelization has prompted informed Vatican journalists to observe that Pope Francis may be hoping to put the Filipino prelate in place to become his successor.

Pope Francis will celebrate his 83rd birthday next week, and his physical condition has never been robust. Although he shows no signs of slackening his pace—and has not recently repeated his earlier suggestion that his papacy would last only “four or five years”—the Pope could be thinking about ways to ensure that his policies will survive beyond his death or resignation—that he will ensure the “irreversible change” that his supporters hoped he would bring to the Church. Cardinal Tagle was already on any informed observer’s list of papabile, and this appointment undoubtedly moves his name up that list. The Congregation for Evangelization, popularly known as Propaganda Fide, is one of the most powerful Vatican dicasteries, responsible for the Church’s work in mission territories around the world. Cardinal Tagle will be watching over about 4,000 dioceses and roughly one-third of the world’s Catholic bishops.