The shapechange spell states that one does not get access to the Spellcasting trait of creatures they turn into:
You transform into an average example of that creature, one without any class levels or the Spellcasting trait.
Does this restriction include monsters with Innate Spellcasting, or does one get the Innate Spellcasting trait of the creature they transform into?
Best Answer
You get access to Innate Spellcasting when using shapechange
Spellcasting and Innate Spellcasting are both separate examples of special traits, as can be seen in the basic rules for monsters. There are even monsters that have both traits, for example, the Drow Mage (note how they even use a different spellcasting ability):
The shapechange spell explicitly states that you do not obtain "the Spellcasting trait" (capitalized even) and not "any of its available spells" or anything similar1 suggesting that only the trait that is called "Spellcasting" in particular is not obtained.
Further, Jeremy Crawford has also unofficially confirmed that these are supposed to be read as being different traits in this tweet exchange that is also about shapechange:
Therefore, we can conclude that using shapechange grants access to the Innate Spellcasting trait along with any other special traits the creature has (except the Spellcasting trait).
1. Noted by Medix2