I don't think there is any evidence yet. I certainly can't see any evidence the epidemic has R0 < 1 anywhere unless there is fairly draconian lockdown.
The epidemic only changes when the population (or critical essential worker bits of the population) get immunity. If you look ta the number of US cases it is not nearly enough for that to happen except just possibly in some peek infection places like NY.
What do you think about those who are exposed to the virus, but never develop antibodies, and how they as a group would affect R0 and herd immunity? Not sure if there is even such a category, but as you know, some of the tight knit communities hit hard by COVID, and subsequently tested, generally were found to have only about 15% with antibodies.
Within the tight confines of an aircraft carrier, cruise ship, small town, or a 3 generation household, escaping exposure would seem unlikely, yet ~85% showed no antibodies. Remarkable, considering that before the first person fell ill (3-13 day incubation), they would have likely compromised all others via the viral contact transmission chain. Possibly, they missed a sufficient viral dose to trigger their bodies defense, or somehow missed any exposure at all...but unlikely IMO.
So if there is such a group, and they are resistant to the virus, but when tested show no antibodies, I am curious how they are to be accounted for in all this? Example being; it is said we need 60-70% to achieve herd immunity, but that is determined by the number of people showing antibodies.