Mickey mouse as a concept will enter public domain. Although with a trademark, it will be hard to do a Mickey mouse animation. See Sherlock Holmes. Some, but no

Mickey mouse as a concept will enter public domain. Although with a trademark, it will be hard to do a Mickey mouse animation. See Sherlock Holmes. Some, but not all of Sherlock Holmes is on public domain. Also note that trademarks expire, they have to be renewed. In addition, you can lose a trademark. See Kleenex, escalator, zipper, bandaid, etc.