Tamron has shown off their first full frame E-mount lens Tamron 28-75mm f/2.8 Di III RXD lens (B&H Photo Video) at CP+ Show 2018. The US price for this lens is not available yet, release date is in April-May, 2018.
You can see additional info about Tamron 28-75mm f/2.8 Di III RXD Lens here.