Carlos is the husband of Valentina, who is the sister of Jorge. Jorge is Luis's father, which makes Valentina Luis's aunt. Consequently, Carlos, being Valentina's husband, is Luis's uncle by marriage.

Miguel is the son of Valentina and Carlos, which makes him Jorge's nephew since Valentina is Jorge's sister. Isabel is Jorge's daughter, and because Miguel and Isabel share an uncle (Jorge) and aunt (Valentina) relationship through their parents, this makes Miguel Isabel's first cousin.
Jorge has a sister named Valentina. Valentina is married to Carlos and they have a son named Miguel. Jorge is married to Sofia, and together they have a daughter named Isabel and a son named Luis. Describe how Carlos is related to Luis and how Miguel might be related to Isabel.

Make your response very short.