The last decade has been pretty good for many cities. Recent 2020 Census data tells us that of the 50 largest cities in the US, 46 of them grew their population over the last 10 years. On average, these 50 cities grew by about 8.5%, compared to 5.6% for the decade between 2000-2010.

As you might expect, the fastest growing cities tended to be in the south and the west. The top 3 fastest growing cities over the last decade were Fort Worth (24%), Austin (21.7%), and Seattle (21.1%). The cities with the biggest population declines were Detroit (-10.5%), Baltimore (-5.7%), Milwaukee (-3%).

It's important to keep in mind that city boundaries can skew these numbers depending on how they are drawn. A declining "city" population doesn't necessarily mean that the broader urban area is losing people. Though it does still tell you something about the "city."

Another thing that happened over the last decade is that most of the largest US cities continued to become more diverse. In 2000, white populations were a majority (>50%) in 25 of the 50 largest cities. This dropped to 17 cities in 2010 and then 14 cities last year (2020). Meaning that 36 of the largest cities are now "white minority" cities.

For more data check out this recent article from Brookings.