A point that has been hammered home by everyone involved with Black Widow is that the core theme of the movie is "family," with Scarlett Johansson saying the movie will ask questions about the subject.
“What is family? How does it define us? How does our past define us? How does our family – however we define it – make up who we are, for better or worse?”
Other actors like David Harbour also pushed this notion of the movie being about family, describing familial scenes like the awkward dinner table conversation seen in the trailers and more. Between Johansson's Natasha, Harbour's Alexei, as well as Florence Pugh's Yelena and Rachel Weisz's Melina, things could get complicated, in a good way, especially given some official new descriptions for the characters.
Pointed out by a user on the r/MarvelStudiosSpoiler subreddit, there are new character descriptions for Natasha, Yelena, Alexei, and Melina on a Latino Disney website for Black Widow.
The following character descriptions come from Reddit user u/Black_Widow246800.
Separated from the now fractured Avengers, she faces the dark path that led her to become a spy and assassin and the events that took place afterwards. A little reluctantly, she reunites with an unlikely group of spies who are part of her past and share with her a fundamental part of her story, as well as the desire to prevent a lethal force from being triggered. However, her efforts are threatened by a deadly killer whose exceptional skill set is different from everything Natasha ever faced.
A product of the Red Room's ruthless training program, she keeps a secret history with Black Widow and is determined to solve it. When Yelena finds herself trapped in a world full of dangerous threats around every corner, her only chance of survival is perhaps through a fragile truce with the person she blames for a lifetime of torment: Natasha Romanoff.
The Red Room's response to Captain America is a super soldier and spy who lived a lifetime of triumphs during the Cold War. Alexei's years of espionage have been left behind, but he is still considered the ultimate hero. He loves to share his greatness with those around him, which these days includes the other inmates of the Russian prison where he resides. Deep down he feels guilty about his spy life, especially Natasha Romanoff, whom he met long before she became Black Widow.
She is a highly specialized spy agent who has gone through the Red Room training program four times. After several covert missions, one of which involved the young Natasha Romanoff, the Red Room recognized Melina's intelligence by making her one of its leading scientists. After decades of service, Melina has managed to distance herself from the Red Room, but when Natasha shows up, Melina will have to decide which side her loyalty is on.
WHAT THIS MEANS
There are some tidbits of new information in these descriptions, such as further confirmation that Natasha has never faced someone with Taskmaster's "skill set." However, that itself could have been inferred from previous trailers when Natasha asked Yelena who Taskmaster is, but now fans know for sure that Black Widow has never encountered someone with Taskmaster's abilities at all.
As for Yelena's description, this does indicate that she blames Natasha "for a lifetime of torment," which could mean a lot of things. It could be how, after she defected and joined SHIELD, Natasha left Yelena behind in the clutches of The Red Room or maybe even that Natasha recruited her in the first place.
Alexei actually has two interesting pieces of information, one that was already assumed based on the character and his history, but also his prior relationship with Natasha "long before" she became Black Widow. It says that Alexei, Red Guardian, has "lived a lifetime of triumphs during the Cold War," which could point to Alexei being much older than he looks.
The Cold War lasted from 1947 to 1991, and the description said that he spend a "lifetime" being in this war. In the comics, Alexei was turned into the Red Guardian by the KGB, which was established in 1954. If this is indeed the case, then it could mean that Alexei has some form of the Infinity Formula from the comics that prevents or slows aging or that he was frozen at periodic points, similar to how Bucky was during the latter half of the twentieth century. However, this could just be a case of hyperbole and that "lifetime" descriptor may just be an exaggeration of his time spent in the war.
Finally, Melina, who's description actually gives the most new information out of the four, saying that she was "one of [The Red Room's] leading scientists." Melina has no significant history a scientist of any kind in the comics and was just a standard assassin. Another interesting tidbit is that Melina had to go "through" the Red Room training program four times, which seems to further push the notion of her not being much of a fighter. Although, it does mention that she had gone on "several covert missions," but it could have been in a non-combative capacity.
This description of Melina may make some fans suspicious of her, considering her lack of screen time in the trailers thus far, especially when the description for her character ends by saying that she "will have to decide which side her loyalty is on."