The only other spy thriller in the MCU, Black Widow plays on the heartstrings of the audience, covering Natasha Romanoff's tragic backstory. The movie recounts the events just after Civil War and before Infinity War. They maintain the same graphics as in Civil War, displaying the city names in large white fonts.
MCU fans will finally discover what Nat and Barton meant when they dropped a mention of Budapest in both Avengers I and Avengers Endgame. It's this inside reference that points to an adventure or an experience they both shared. The movie focuses more on the emotional elements of the Black Widow's past.
Human trafficking is referenced in this movie through the Red Room which is a facility that trains abandoned children to be assassins. Of course, there is a lot more nuance to this, and I won't go into the details to avoid spoilers.
The main plot device in this movie is mind control, more commonly known as brainwashing. This is referenced in various movies across the MCU, Loki using the mind stone on Barton, and Nat confessing to Barton on the Shield carrier about knowing what it means to be "unmade." There's also Wanda Maximoff's "mind games" (quoting Ultron here) which dismantled the Avengers in "Avengers: Age of Ultron". The mind control in Black Widow has real-life parallels and a long history across the world.
A book called the Gulag Archipelago by Aleksandr Solzhenitsyn discusses how political dissenters in Stalin-led Russia were sent to labor camps called Gulags. Here various techniques were used to extract information from the inmates through methods such as sleep deprivation, use of insect pests on the inmates (bedbugs), and extreme isolation.
Don't know what to watch? Subscribe for a free streaming guide to Netflix, Hulu, Amazon Prime Video, Disney+, and HBO Max