Generally most of them had black op histories which involved illegal kills. Authority is likely to offer some deal so they won't be punished for their criminal past. Other than that, each one has some personal trouble or reason kind of thing. Below is my analysis.
After the settlement with Hawkeye, it's a little unexpected she still works with/for Contessa. What's new talks her into it is not very clear.
With Belova in the team, this one should be easy. Father's love.
The only guy who is not a former villain, though lost some reputation and popularity. It must be the patriotism and his will to make up.
Probably she still needs some technical care for her life. Government has money.
Personal reason is not very clear. Perhaps simply an exchange to avoid being locked up.
The puzzling one. After Endgame, he should be legally free from his past. There won't be much reason for him to work for government either. If he joins the team, it's more likely he volunteers. I assume something happens before this movie that gives him a big reason, like event in Cap 4.
Your thought?
