Is Rick Riordan making a new book after mark of Athena?

Rick Riodan has written several books after The Mark of Athena, including The House of Hades, The Blood of Olympus, The Lost Hero, The Son of Neptune, The Mark of Athena, The Hidden Oracle, The Dark Prophecy, The Burning Maze, The Tyrant's Tomb, The Trials of Apollo, and more recently, The Sun and the Star and The Tower of Nero.