They have different meanings and usages. "Mislead" is used in all tenses to mean " to deliberately give false information" it is a verb or a predicate adjective in the form "misled". It can't be used as an adjective before a noun. I was misled. He misled me. Don't let him mislead you. He will be misled if he listens to John. He will mislead Mary with his story. "Misguide" is rarely used as a verb and then almost always in the past. It is usually in the adjective form "misguided" and can then be used for any time. It means "not informed" or "not based on the true situation." He unintentionally misguided me by telling me that John was at home. Their effort to solve the problem was misguided. That was a misguided effort.

"mislead" is a more intentional act. "misguide" could be accidental or intentional.

Thanks again for your help. Wish you have a great day!

Helen I forgot to add that the adjective form "misleading" is what you'd use before a noun.