As someone who is currently working on rewatching the series in my spare time, here's what I've noticed. (These things are mostly from Season 3.)

When doing certain spells, Nico's eyes do the thing that Kaecilius and his followers' eyes did.

Morgan Le Fay has the Darkhold.

Cloak and Dagger make a guest appearance.

I vaguely remember them mentioning Wakanda.

The Dark Dimension appears too.

Alex Wilder has some pez dispensers of Spider-Man, Iron Man and Captain America.

Okay thanks guys :D

It largely doesn't and serves as a standalone. There are connections which are mentioned above, but it's mostly its own show and I honestly admire it for that.

Although it has some ties to the larger MCU. Kevin Feige said that the only shows that are cannon in the MCU are the Disney + shows. Marvel TV shows take place outside of the main timeline.

@PTB010307 oh really... When?

Oh right. Never. He has never said such thing. The shows are canon.

Kevin Feige Confirmed That Series Are Canonical By Putting Jarvis Into Endgame.

^ Kevin Feige confirmed the shows are all canon by saying so multiple times in interviews. All shows are canon until they are confirmed not to be and this includes Runaways

Hope for the best... be extremely annoyed if its the worst