Obviously not all the characters are in Overwatch but you catch my drift. What does the character do for a living in an alternate universe.
Ana would have played center field for a baseball team. Nobody makes it to home plate before the ball gets there.
Lucio is pretty obviously still making music.
Rein is his universe’s Arnold Schwarzenegger.
Sym would still be where she is…
I think all of the soldiers and scientists would stay pretty much as they were.
Tracer would probably be irreparably zooming through time and space though… :<
Genji: Dead
McCree: Jail
Rough times for the Blackwatch boys.
But really Omnics would rule the world… Cause Overwatch didn’t bet them
Mercy would have the ability to resurrect multiple people from the dead as a necromancer. And look good doing it.
~Sincerely Yours xoxo,
a Lover of True, Fair, and Fun Balance.
xavvypls 
Tracer only has her condition BECAUSE of Overwatch though
Widow would not be brain washed because talon would not need her, and she could live normal life.
Do he now? Ashe and her gang didnt look like they been lock out, so he would propably be with them i guess?
Genji: Dead or rescued by Talon
Reaper: Alive
Reyes caught Mccree, if OW didn’t exist, I doubt he’d be in jail.
Probably just jailed by police and wouldn’t have been trained by Ana.
Again only Omnics would be alive (cause they won the war)
If it never existed?
Rein would be a drunken wreck after his master was killed, and would never have been given the Overwatch badge. The omnic invasion would never have been stopped and they would all be living in a dystopia AI controlled world.
Tracer would be normal/stuck in a time loop because Winston never came to Earth or did and got captured so Widow would successfully kill Mondatta, or it would be fun to imagine that the King’s Row event never takes place because she never got brainwashed and lives a normal life and he becomes some tyrannical/peaceful leader of the now in control Omnics.
Several of the characters would probably attempt small pockets of resistance in a Skynet fashion.
Okay, I’m just ignore the fact that without Overwatch, the Omnics would of won and assume that humanity won through some other mean or that the characters never joined Overwatch in the first place.
Well the major changes are
Gabriel Reyes never becomes Reaper and joins Talon
Widowmaker is never brainwashed
Without Blackwatch, it’s likely that Moira would of been recruited into Talon sooner than in canon.
Since Mercy never joins Overwatch, they don’t get their hands on her nano-medicine and Ana’s biotic rifle is never made.
Ana continues to serve in the Egyptian military and never fakes her death.
Genji dies
McCree is thrown in Prison or continues to be part of the deadlock gang.
Tracer never gets Chronal Acceleration.
Winston still crash lands on Earth but ends up joining another organization.
Mondatta is never killed though it’s possible someone else from Talon might do it.
Now here characters that would largely remain the same
Lucio, Symmetra, Hammond, Junkrat, Roadhog, Sombra, Doomfist, Baptiste, DVA, and Zarya are all largely unaffected by the absence of OW assuming that the Omnic crisis plays out the same even without them.
Doomfist would have been able to wreak havoc longer, as there would be no Winston there to out-punch him and imprison him.
Oh right. So Doomfist remains the leader of Talon for much longer.
Antonio and Vialli would also be alive.
[No “You’re Right!” followed by a Hellfire Shotgun to the chest]
[No need to FUS RO DAH Vialli over a bridge]
Doomfist would potentially have to fight Antonio himself.
Antonio was part of Talon. Why would Doomfist fight him unless he has a reason too?
Power, all of the members of Talon crave it in one way or another.
If Doomfist wants to truly start a war, he must be the head of it all.
Probably enslaved or used as batteries by the Robot Overlords, considering it was Overwatch, the team of 5 people, that pretty much saved the world.
In all seriousness, you have to specify what you mean. Does the Omnic war thing still happen? If so, does humanity still win? Assuming it does, does the world just resumes to function and rebuilds? Does Talon still exist?
If we assume everything is the same as the current universe, except Overwatch (in all it’s forms) never happened, then
Soldier would probably leave the army, get married and have a family, like he wanted to.
Widowmaker would remain a professional ballet dancer, but would never become purple, since it was her husband’s connection to Overwatch that caused Talon to kidnap her.
Tracer would never have her accident and would just be a normal girl. Possible she wouldn’t even become a pilot.
Ana is still world’s best sniper, but her relationship with her daughter is different - there’s no Overwatch, there’s no dream of joining it.
Pharah might still join the army, but her desire to do so isn’t influenced by literal heroes surrounding her since childhood.
Mei is still a climatologist, but she never gets stuck in Antarctica, since it was an Overwatch mission that got her there.
Reaper still goes through SEP, along with Soldier. And if his smoky condition is caused by SEP, it will still happen. However, he never hires Moira, meaning she could never “”“fix”"" him, so he’d probably never become Reaper Reaper.
Mccree and Ashe still meet, Deadlock still happens, but there’s no Blackwatch, there’s no Commander Reyes to give him a choice of prison vs. redemption. If Deadlock is busted by another force, he’d probably go straight to jail.
Genji and Hanzo still have their fight. But there’s no one to save Genji. He dies.
Alejandra never gets her money back from Los Muertos. Her family’s bakery never gets flour that night.