Japanese website Nikkei recently posted an article about upcoming Nikon full frame mirrorless camera. They bet Nikon will announce their first full frame mirrorless cameras in the second half of 2018, around Photokina in September. And release date is in early 2019.
Tamron recently announced their first full frame mirrorless lens for Sony E-mount mirrorless cameras Tamron 28-75mm f/2.8 Di III RXD lens. According to recently interview with Tamron executives by dpreview, Tamron is ready for upcoming Nikon full frame mirrorless cameras.