I'm not sure what's up with this and the future. This was considered technically a "mini-series" so it could exist as a stand alone entity. But Fargo on FX was also considered a mini-series and it's getting a season 2 but set 30 years in the past.
My guess is there will be a season 2 but with a completely different storyline. Maybe start making different seasons about different archaeological finds that work into different conspiracy theories and world events.
I can explain part of that. The new trend for some networks is to create a show, advertise it as a mini series, and launch it. that way if it doesn't hold up the viewership they can just end it and be done, but if it holds a decent viewership then they can renew it.
The name of the show is "Dig" though, so if it gets renewed does every season have to incorporate archaeology in some way?