For example, I'm a professor at the University of South Carolina. Here we've had around 2,500 confirmed Covid cases, and perhaps around 10,000 cases in actuality. Nearly all of them happened in the first few weeks of the semester, and now the positive test rate is extremely low.
Looking around town, it's pretty clear what happened. There are some students that have acted like nothing is happening, partying and drinking constantly. That population has presumably hit herd immunity already. Meanwhile, there are many students (and staff) that are exercising precautions, and not venturing out a lot, and probably few of them have contracted the disease.
Now, we can't just go back to normal, or else cases would spike among this second group -- but locally it seems that we can afford to relax a bit.
And, also, we're at 8.8 million confirmed infected -- the actual numbers are presumably much higher.
https://covid19.healthdata.org/global?view=infections-testin...
https://covid19.healthdata.org/united-states-of-america?view...
But notice, in the latter chart, that in the US the number of infections is predicted to peak in January and then start going down. It seems plausible that by March, we'll achieve some level of herd immunity, relative to the precautions that are currently being taken. We might have a situation like Europe over this pas summer, with small numbers of cases until a second spike in Fall/Winter 2021. That would buy us the spring and summer to roll out a vaccine.
Of course, I'm far from sure that this is what will happen -- but it certainly seems plausible to me.