The seasonal flu alone kills half a million people every year. So any mild disease that is as contagious and barely twice as fatal will kill 1 million. And that's what's going to happen with COVID19. It is far more severe than the flu.
We know COVID19 is as contagious, given how fast it's spreading and how unstoppable it is (R0>2, asymptomatic transmission, airborne). And we now have 4 independent estimates that place the Infection Fatality Ratio at about 0.5% to 1.7% which is between 5x and 17x deadlier than the flu (0.1%): https://twitter.com/zorinaq/status/1230977769795776512 Incidentally, this makes COVID19 comparable to the 1918 Spanish Flu (IFR ~2%) according to experts (see link above). And keep in mind the IFR, unlike the CFR, is the metric that takes into account undetected mild cases. The Case Fatality Ratio is around 9% right now.
So based on this, I predict it will go pandemic and will kill 1 million, and probably a lot more.
COVID19 is the most severe (ie. contagious + fatal) airborne disease since the Spanish Flu.