Read The Dynamics 365 CRM Form TAB Using Java Script

To use the Dynamics 365 CRM form tab, you have to use this ui.tabs.get("TabName") method.
Now hide and show the TAB

// To hide TAB: true=Hide

formContext.ui.tabs.get("TabName").setVisible(true);

// To hide TAB: false=show

formContext.ui.tabs.get("TabName").setVisible(false);