At BlizzCon we talked about these Allied Races coming in Patch 8.1.5. It might feel like a new patch day with the season update and raid opening up today, but this is still the continuation of the Tides of Vengeance story. We will have more information on the Zandalari and Kul Tiran soon!
There will be no raiding required. Some people may have seen the requirements on the PTR and we do plan to talk about them more to help spread the word.
As it currently stands, if you do the Zandalar quest arc (through the Blood Gate quest and Zul’s death), the War Campaign through the Marés da Vingança
achievement, and get Exalted with the Império Zandalari
you will be able to do the questline to get access to the Zandalari Allied Race as soon as 8.1.5 goes live.