Copyrights protect creative expression. Trademarks protect brand identifiers. The owner of a copyright has an exclusive right to make certain kinds of uses of an original work of authorship, whether for commercial purposes or not. A trademark owner has an exclusive right to use a particular word, phrase, logo, etc. in commerce to identify the source of a product or service.
A work of authorship has to be original and sufficiently creative to receive copyright protection. Trademarks do not need to be original or creative.
The key requirement for a trademark is use in commerce as an identifier of the source of a product or service. A work does not need to be used in commerce as a brand identifier to receive copyright protection.
In some cases, rights in a work of authorship may be protected by both copyright and trademark laws. For example, a drawing of a cartoon character could be protected by copyright law if it is sufficiently creative and original. It might also be protected by trademark law if it is used in commerce to identify the source of a product or service.