Can I download GNOME terminal on macOS?
No, there is no way to run GNOME terminal app in macOS or change the built in Terminal.app to GNOME terminal.
There are third party terminal emulator apps such as iTerm2 available for macOS as well with other features.
macOS Terminal.app provides bash as the default shell. If you use a different shell in GNOME and would like the macOS Terminal.app to use it as well, it is possible to do so.
Both macOS Terminal.app and iTerm2.app supports multiple tabs in a single app window, thus enabling the user to run multiple sessions concurrently.