Apple's #WWDC2019 (Worldwide Developers Conference) was held on June 3-7.
macOS's next big upgrade will be called Catalina and with it comes a big change for developers.
By default macOS releases till now used bash as the default shell. New user accounts in macOS Catalina will have zsh as the default shell. Zsh is an open source shell very popular and comes with a ton of features.
Zsh is very popular in dev community and can be installed in pre Catalina macOS as well. Zsh and Iterm2 (https://www.iterm2.com) goes very well together and improve the developer productivity.