They’re both amazing exfoliants. Glycolic acid has a small molecular size, meaning it penetrates deeper into the skin. It’s wonderful for texture, hyperpigmentation and acne.
Latic acid has a larger molecular size, meaning it doesn’t penetrate into the skin as deep as glycolic acid. It’s great for drier and sensitive skin types because latic acid is amazing at maintaining moisture and softening the skin.
Both are AHAs, meaning you’d need to wear sunscreen because both of them will make your skin photosensitive.
To use them together would not be the greatest idea because it would most likely overexfoliate and damage your skin barrier. So, it’s best to use one or the other.