Has Prophet Jesus, peace be upon him, passed away or is he still alive, and what is the wisdom behind his ascension and his return at the end of time?

Jesus (peace be upon him) is alive and will descend at the end of time. Muslim scholars have reached a consensus on this matter. The wisdom behind his ascension was to honor him and save him from his enemies. Among the reasons for his selection to descend at the end of time is that he is the only prophet among the "Ulul Azm" (Prophets of Strong Will) who is still alive in the heavens. Allah will send him down to establish justice, kill the Dajjal (Antichrist) and his followers, break the cross, kill the swine, and invalidate the claims of the Christians.