Do you guy think a suicide squad styled campaign could work, like a group of prisoners are set to go on a mission. I'm a bit doubtful cause the I've heard that evil campaings don't really work?

I've heard that it works really well for a one-shot, but I'm sure you could extend it into a longer campaign as long as your play group is respectful of each other. Just have a discussion with your group about differentiating the characters interacting from the players interacting. And give them reasons to work together as a team.

Evil campaigns can work, just they’re hard to make work. And they work best with a well established group where the players know each other and will not take character actions personally. 
But a suicide squad kind of thing has a better chance, since while the character’s natural inclinations might be toward evil, they’ve got something keeping those inclinations in check. 
Or you could go a dirty dozen route, where they’re less outright evil and more anti-heroes.

I did this actually, started by asking each player why they would be in a maximum security prison at the start, which a sort of “patron god” breaks them out of and makes them his indentured servants. I found that most players still gave their characters redeeming qualities, (I was counting on it) and now they function more-or-less like a normal adventuring party other than they have to confront really distasteful tasks every now and then which they’ve thus far been really clever about resolving in unconventional, less-distasteful ways. A really fun campaign so far!

Why does a suicide squad group need to be evil? 

The premise is just that they're all thrown together and forced to complete a mission under threat of immediate death. They're expendable and no one using them cares if they make it or not. 

The point is that their individual morality isn't important. It isn't why they're on the mission. They're on the mission to not die.

But they don't have to be evil, either. Just expendable to the powers that have them in it's clutches.

The most important thing when running an evl campaign is to tell the players to make characters which want to be in a group, doing evil things, rather than alone, doing evil things. Also to establish that evil doesn't mean they only care about themselves, they can have attachments and still be evil. Thye just don't care so much about people they don't know.

Kinda depends on the overall demeanor of the party's characters, but I think you and the party should keep a few things in mind:

• What they want/need
• Why getting it is worth the risk
• What the consequences are for disobedience

If they're evil, fine. They can be as evil as they want. But if they're put into a Suicide Squad-esque situation, it's because somebody or something already has some level of control over them. They've been captured, they have a loved one hostage, they have a secret they don't want out, they just want to get out sooner, etc. There's a menagerie of possible reasons why they'd agree to take the risks and especially in a setting like DnD there's an equal menagerie of consequences that could come from breaking code.

In Suicide Squad it's an explosive charge in their neck. In DnD it could be a high level Geas or Disintegrate that activates on command. Lean into the cruelty as the DM. Somebody wants to start mowing down civilians instead of doing the objective? Fine. Kill 'em. It's that simple, in the eyes of what operation is running the show.

The real interest from this, though, would be in hinting at or outright presenting avenues for them to get out from under the boot of these people. Maybe a trapped devil they're tasked with retrieving offers them a contract or among artifacts they're meant to steal from a compound is a powerful magical nullifier that can end whatever effect is keeping them under control. What obstacles could be in the way of them earning freedom? The obvious consequence of being caught is death, but maybe the risk is worth it to the players.

I'm kinda ranting at this point, but I think it's a really interesting idea for a campaign and I could easily see it being really awesome if you put the work into it.

Yeah Geas is basically made for this idea. It handles the "bomb in neck" motivation perfectly. 

And it is as simple as the guy/gal/group pulling strings to have a crystal ball and a blood sample from all the PCs to keep close enough track of their actions. 

A sending spell from time to time to remind them of critical information or steer their progress.