WordPress 5.0 is coming soon and as per the development phase, today the beta 2 of WordPress is released; So,
Gutenberg Editor AKA Block Editor
The WordPress core team has successfully integrated Gutenberg 4.1 to WordPress 5.0 Beta 2 including the new Format API, embedding improvements, and a variety of bug fixes. On WordPress 5.0 beta 2, MetaBox had few rendering bugs but now it is fixed. This is the list of full bug fixed so far. We have 16 open issues now. We are sure to close the issues any soon.
Theme Twenty Nineteen
The theme Twenty Nineteen is still under development but it is merged with the WordPress 5.0 beta 2. You can get a full page theme by default if you install the beta 2. There are some improvements in the theme lately such as: adding the widgets on the footer area of the theme, navigation submenu for mobile devices and improv ed Customizer option with the option of chaining feature image and theme color.
Improvement in the Translation
Other than the above improvements there will be a massive improvement on the RestAPI section too. If you want to try out the WordPress 5.0 beta 2. You can download it from here and use it for your local website. I would not recommend this beta 2 to use on the professional websites owing to having bugs.