Updated: April 2017
You can sync your Gmail account with Outlook for Mac 2016 but you first need to add the account to Outlook. See Add an email account to Outlook 2016 for Mac for instructions.
At this time, Outlook for Mac 2016 support of Google Calendar and Contacts is only available to select Insider Fast participants who have an Office 365 subscription. It will be available to all users worldwide later this year. See Sync your Google account to the Microsoft Cloud for more information.