Blizzard are offering a Dragonflight trial to players with an active subscription but without the expansion!
DF Trial (Source)
For a limited time*, players who do not own Dragonflight but have a subscription or active Game Time can play the new expansion as the dracthyr Evoker beginning today. Experience the Forbidden Reach starting experience for this new race and class combination while leveling in the Dragon Isles up to level 63 in the Waking Shores and through Chapter 1 of the Dragonflight campaign. You’ll be able to experience all the quests, unlock and learn Dragonriding, take your professions to the next level, and even experience two new dungeons during the trial period—Ruby Lifepools and The Nokhud Offensive.
*Dragonflight Expansion Trial access with Subscription/Game Time only available through 2 January 2 2023. After this period, Dragonflight purchase is required for continued access to dracthyr Evoker and other Dragonflight content.