He first announced in June 2015, and I think he'll wait until June 2023 to formally announce again.
He will wait at least until the mid-terms are over to spare candidates from having to declare support for "candidate" Trump; they will have the plausible deniability of saying they will wait and see what President Trump decides and not speculate before then.
-PJ
Agreed. Clearly not a “formal” announcement. He’s saying tonight he’s running (and will win). The formality will indeed come later.