A compound complex sentence has at least Main clause (s) and at least Subordinate clause (s).

A compound-complex sentence is comprised of at least two independent (main) clauses and one or more dependent (subordinate) clauses.

Explanation:

Compound Complex Sentence: a sentence having two or more coordinate independent clauses and one or more dependent clauses

Example: Though Mitchell prefers watching romantic films, he rented the latest spy thriller, and he enjoyed it very much.

Example: Laura forgot her friend's birthday, so she sent her a card when she finally remembered.

Because compound-complex sentences are normally longer than other sentences, it is very important to punctuate them correctly