Like most Superman stories, Lois Lane played a key role in 2013’s Man of Steel. Not only did she uncover Kal-El’s existence in the opening half of the movie, but she also proved helpful in controlling his reveal to the U.S. government and assisting during Zod’s invasion of Earth. It was clear by the end of the movie that she and Clark Kent had struck up a special relationship, and in Batman v Superman: Dawn of Justice, we’ll see how the two being together has changed Lois for the better.
When we reunite with Lois Lane in the March blockbuster, she has moved in with Clark, and Amy Adams informed Empire (via ComicBookMovie) that Clark has had a positive impact on her as a journalist. She said:
[When] we met her before she would do anything to get the story - now Clark has instilled some faith in humanity in her. Her relationship with Clark is the closest thing she has to anything faith-based, you know? Although moving in with Clark brings issues.
Amy Adams wouldn’t elaborate on what these issues are, but pointed out that because Clark is an alien, it’d be impossible for them to have a normal relationship. The actress also mentioned that Lois is "too busy sleuthing" to appear alongside Wonder Woman in the movie, but reaffirmed that she will have scenes with Batman. In Man of Steel, Lois definitely had that drive to pursue a story no matter what, but its sounds like Clark’s optimism has rubbed off on her and given her a new perspective on life. Then again, you tend to have a lot of faith in someone when they’re a nearly-invincible, multi-powered alien.
With all the Batman v Superman: Dawn of Justice attention focused on its heroes and villains, there hasn’t been much revealed about what Lois’ role in the movie is. Aside from a few brief shots here and there, there are two important moments featuring her in the previews. The first (from the Comic-Con trailer) is when she is reminding Clark that the ’S’ on his chest (a.k.a. the El family crest) stands for hope, which is important to the people of Earth. The second (from the December trailer) is when she’s apparently been taken captive by Lex Luthor, and when she criticizes his evil plan he gives her a flick to the forehead (here’s hoping she gets to hit him later for that). Amy Adams also mentioned last year that Lois will be the "key to the information" in the movie, so she’ll putting everything together while the eponymous heroes are duking it out.
We’ll see Lois again when Batman v Superman: Dawn of Justice is released on March 25, and Amy Adams will also reprise the Daily Planet reporter for Justice League: Part One on November 17, 2017.