When CBD companies refer to homeostasis they’re referring to the role that cannabis compounds (cannabinoids) can have in maintaining balance via the Endocannabinoid System (ECS).
From Kahn Academy:
Biological systems like those of your body are constantly being pushed away from their balance points. For instance, when you exercise, your muscles increase heat production, nudging your body temperature upward. Similarly, when you drink a glass of fruit juice, your blood glucose goes up. Homeostasis depends on the ability of your body to detect and oppose these changes.