I’m based in Mayan calendar… and my own calculations the release will be 12 may 2022.
I think it will come out 2020 and we’ll get a new Definitive Edition this year.
This year we will have Age2 DE, early 2019 Age 3 HD and Age IV in late 2019
Early 2019 + maybe more sometime to release other defenitives. See PR campaign for halo wars 2, announced in 2015, first info in 2016, released in early 2017.