There are plenty of new and returning action RPG players who have never participated in seasons before and Rebirth could make it slightly less confusing. In Diablo 3, Seasonal Rebirth was a feature that allowed players to transform their old non-Seasonal characters into Level 1 Seasonal characters, mailing their old non-Seasonal gear to their Stash. Maybe it's a bit of a stretch at this point to read 'yet' to mean that it's definitely coming, but it's a good sign that they're aware of it regardless. The image above shows information about Seasonal Rebirth from Diablo 3.

'Rebirth isn’t a feature in D4 yet,' Fletcher wrote. The new character customization options in Diablo 4 would make a Rebirth feature even more valuable than in Diablo 3, and, according to global community development director Adam Fletcher, 'the team is aware' that people would love to see this added in the future. The character reduces back to level one and has all its gear stripped. That might not sound like much of an improvement-and it's really not-but you at least get to keep playing the same character you may have gotten attached to, and you can keep doing so every season. Rebirth lets you select one of your non-Seasonal characters and transform it into a Seasonal character. Its Rebirth feature lets you transfer an existing character over to a season, but all their items stay behind and they start the season at level 1. It turns out, Diablo 3 has had an answer to this for years now.

Diablo 3 rebirth feature