For authors who are working in traditional publishing, almost always it is best to stick with one genre until the third book.
Publishers want to keep the foundation of readers generated during the first book’s sales life and build on that with a second book that is in the same genre.
One you have a third book out, you and your agent can discuss whether you have enough name cache to be able to switch genres. If you do, you can switch to something similar.
If you have achieved bestseller status before then, of course, you can write just about anything you like!
Self-publishers should also take this advice but work it a different way. Target all your marketing to specific genres. Only overlap when you know a particular promo will reach readers of more than one genre. This allows your marketing to be more effective, and saves time and money.