From WordPress.org: WordPress 5.5 is the second major release of 2020 and aims to include a navigation menus block, automatic updates for plugins and themes, a block directory, XML sitemaps, lazy loading, and update Gutenberg to the latest release version as we continue to focus in 2020 on full site editing via Gutenberg.
By far, the most interesting functionality is the automatic updates for plugins and themes. From a security point, that can be quite a benefit. From a hosting view, this could slow down malware infections on sites that are ignored and not maintained. From a developer’s view, that is somewhat scary as websites may break after a plugin or theme is updated. And unfortunately, none of this helps with the whole problem of un-updated premium themes and plugings. Regardless, it’s definitely a step in the right direction.