Project Server 2016, on premises, Released to Manufacturing (RTM) version is released last week.
Project Server is fully integrated within same SharePoint installer, and once SharePoint installation will be completed, Project Server service application will be available to be used.
Microsoft has also announced that Project Server/SharePoint 2016 will be generally available in Microsoft Volume Licensing Service Center in early May 2016.
You can refer to my last blog to follow step by step to stand up SharePoint 2016 farm: http://khurramjamshed.blogspot.com.au/2015/12/sharepoint-or-projectserver-2016.html
Project Server 2016 RTM to download: https://www.microsoft.com/en-us/download/details.aspx?id=51493
Language Pack for SharePoint 2016: https://www.microsoft.com/en-us/download/details.aspx?id=51492
Project Server 2016 tech-net documentation: https://technet.microsoft.com/en-us/library/cc303399(v=office.16).aspx
SharePoint Server 2016 tech-net documentation: https://technet.microsoft.com/en-us/library/cc303422(v=office.16).aspx
Whats new for Admins in SharePoint 2016: https://blogs.office.com/2016/03/14/whats-new-for-admins-in-sharepoint-server-2016/