https://www.bing.com/images/search?q=tank%20man%20china
(For those who don't see results, this is my screen grab of the above at 18:12 UTC : https://imgur.com/a/3tzPV49)
Also, "Tiananmen Square massacre" still returns some image results:
https://www.bing.com/images/search?q=Tiananmen+Square+massac...
Therefore, the tweak for "tank man" doesn't seem to make any sense since all the other phrases to get to the same sensitive topic are not suppressed.
(I did some searching.) This is from a report here:
https://www.msn.com/en-gb/news/world/microsoft-bing-raises-c...
Of course, the search result is an MSN link.