Guardians Of The Galaxy Vol 2: 20 New Details Just Revealed

After their sibling rivalry was established in the first film, we're going to see lots more of the dynamic between Gamora and Nebula, whose backstory will be explored more. But, regardless of their relationship with their "father", he won't be a presence at all, because it's absolutely not his story:

"First of all, it’s about two sisters. It’s not about the sisters and their father. It’s about two sisters and what were the sisters’ problems with each other. And yeah, some of those things were caused by being raised by the ultimate abusive father. But it really isn’t about Thanos, and frankly I just wasn’t inspired to put him in the movie. I kind of go with my gut on these things and it just wasn’t what I wanted to do."

Gunn says writing Thanos wasn't fun for him last time, and his daughters' relationship is between them as opposed to being with their father.

Luckily, Marvel were good enough to allow Gunn to make the sequel a stand-alone, which takes some of the pressure off him, as he's not a director who tends to look forward to his next projects:

"It makes me miserable, and by the time I get to that other project is usually not what I want to do. So, I’m doing Guardians Volume Two and then after that am I going to do Guardians Three, am I going to do something else with Marvel? I really, really don’t know. We’ve talked about it. We talk about it all the time. Is it what I want to do, I don’t know. I honest to God don’t know."

So don't expect the film to tie too much to what comes after it, even if the feel will definitely influence Thor: Ragnarok.