Marvel's Runaways is now streaming on Hulu, which means the teenage superhero team has officially joined the Marvel Cinematic Universe. But that doesn't mean people should expect them to show up in Avengers: Infinity War fighting alongside the Earth's mightiest heroes. Marvel TV and Marvel Studios are connected to each other, but they both operate different parts of the steadily growing shared universe. And in order to allow both sides to thrive, they've generally remained narratively unconnected. Unfortunately, that's not going to change with Runaways.
Hulu's Runaways is about a group of teenagers who discover that their parents are supervillains and members of a group collectively known as the Pride. The six teenagers reject their parents upon seeing them perform a ritual and essentially run away together. Aside from having superpowers and villainous parents, the Runaways TV series and comics typically deals with common teenage issues, and that doesn't jive well with the overall MCU theme, which will soon be dealing with universe-altering events when the Avengers go up against Thanos and his loyal Black Order.
Related: Runaways: Characters & Powers Guide
Still, it's possible that both Marvel divisions will one day work together to bring the various corners of the MCU together, with Agents of S.H.I.E.L.D. crossing over with The Defenders and eventually the Runaways. Similar team-ups have happened in the comics, though not to the extent that non-comic book readers may hope for. Runaways will likely never crossover with the Avengers, but that doesn't mean there isn't room for potential mini-crossovers with certain characters and teams from other sides of the shared universe - or a different version of the Avengers team.
The closest the Runaways came to working with the Avengers in the comics was once teaming up with the Young Avengers - consisting of characters such as Vision, Hawkeye (Kate Bishop), and Speed - during the Marvel Universe's Civil War crossover event in the 4-issue miniseries, Civil War: Young Avengers/Runaways. Considering that the MCU's Civil War arc has already come and gone, and didn't overly affect the TV-side of the shared universe, it's unlikely that Marvel TV will suddenly create a Young Avengers group at this stage in the MCU for the Runaways to team-up with. Marvel Comics also turned the Runaways team into the Young Avengers in a mid-2000s What If... storyline, but that probably won't happen in the MCU, even though it would certainly be interesting to see.
The superhero team's comics have typically remained apart from the core Marvel Universe since they were initially published under Marvel's Tsunami imprint and later as digests. While the comics certainly attracted new readers, one of their biggest draws was that they were about somewhat regular people living seemingly regular lives and the comic series became more about the teens discovering their heritage and harnessing their powers rather than preventing the end of the world.
What's more likely is that the Runaways could crossover with various Avengers members, such as Doctor Strange, considering certain connections between the two properties - but for now, it seems their connections are relegated to merely to objects and references. As a general rule-of-thumb: if S.H.I.E.L.D. and Defenders aren't crossing over with the Avengers, then don't expect any other show to do so, especially Hulu's Runaways.