A long time after Inarius and Lilith had Diablo 4 Gold secretly created Sanctuary to the Nephalem - the offspring of angels and men - the Council of Archangels was formed to decide humanity's fate. It was Tyrael who cast the final vote and therefore he will be held accountable by other members of the Angiris Council, leading to his death before the events in Diablo 4 all for the good of mankind. His role in the coming game is unclear at present, but there are some plausible ways this important character could be involved in the future of Diablo.
Diablo 3 is a deep dive into Tyrael's saga, in which he is transformed into the Fallen Star by tearing off his wings and crashing into Sanctuary in which the descendants of Nephalem are residing. As he joins forces with a powerful descendant, Tyrael defeats the evils of the prime and takes the control of his Black Soulstone. In the event that Archangel of Death, Maltheal, went after the stone and became angry with all his comrades It was Tyrael who had his companion sent to Pandemonium to end death itself.
Tyrael chooses to keep his mortal form , but reunites with his angelic brethren and becomes both his Aspect Justice and Wisdom. Diablo 3 ends with him looking to see if his mortal friend, who might be corrupted, should be the new threat towards Heaven, Hell, and Sanctuary or the very existence of life itself. There's a reason that Aspect of Justice and Wisdom probably won't stand by while Inarius marches an army upon Hell in search of his former love, Lilith.
The most recent Diablo 4 cinematic trailer from Blizzard features Inarius fighting Lilith and armies on both sides. While this footage doesn't show Tyrael's direct involvement, his invention of Horadrim as well as his influence on the Paladins from Sanctuary suggests that he's in the game. Dark and light battle over the course of battle. the now-mortal Tyrael resides somewhere in the middle.
It is possible that his presence will be felt through these intermediaries until circumstances force his hand. Tyrael continues to feel the consequences of the destruction of his Worldstone at the end of Diablo 2. That mystical artifact protected Sanctuary from Heaven and Hell and he stands as protector over the land on its behalf. Tyrael seems unlikely to lead any further charges into Hell or venture much further beyond the Pandemonium Fortress, where he could offer advice as Deckard Cain to cheap Diablo IV Gold those who will stay and listen.