Deathstroke will be able to survive something Deadpool can’t.

Some similarities between certain Marvel and DC characters cannot be overlooked. The perfect example of this would be Deathstroke and Deadpool; also known as Slade Wilson and Wade Wilson. The two characters have been compared to each other ever since they existed only in comics. The one thing that has stayed constant is the question about who might win a fight between the two.
Deathstroke in DC Comics
While Deathstroke has the ability to heal himself and is an excellent swordsman and shooter, Deadpool is simply overpowered, being an extremely strong fighter, and not to mention, immortal. While many would stop the conversation here and accept the answer, there is one scenario where the Merc with a Mouth would be at a loss and the assassin would win.

Deathstroke Vs Zombies

During the DCeased arc of the DC Universe, some of the strongest and most beloved characters could not stand a chance against the Anti-Life virus. However, there was one character who was able to walk through unscathed; for the most part. Throughout the entire story. Deathstroke was bitten and ‘infected’ by the virus several times without turning into one of the Anti-Living.
Deathstroke in DC Comics
Although symptoms of the virus do begin to show for him, they quickly dissipate thanks to his healing abilities. Deathstroke’s healing works much differently than other characters like Superman, who also succumbed to the virus. Where other bodies focused on healing the diseased cells, Wilson’s body killed those cells and focused on making new ones, which allowed him to live another day.

Deadpool May Not Win Against Zombies

The one thing that seems to have stayed constant through all versions of Deadpool is his immortality. Wade Wilson has been de-boned and turned into a cape, ripped apart by the Hulk, and impaled on an elephant tusk, only to have survived and come back with a sarcastic remark on his tongue. When such a concept exists in any form of fiction, a loophole is always found, and those who are seemingly eternal fall the fastest. It would seem that the curse of the immortal follows him too.
Deadpool in Marvel Comics
Deadpool, famously played by Ryan Reynolds in the MCU, has had to face off zombies more than once, and the way that things go down for him changes drastically throughout these versions. In some versions, he does turn into a zombie, becoming a talking head called Headpool or losing his regeneration ability due to the virus. In other versions, he becomes an endless food source for the living dead and accidentally helps them gain intelligence.
Zombie Deadpool in Marvel Comics
In one specific version, he becomes a zombie but is able to keep his powers and intellect. The unfortunate thing in this version was that in an attempt to heal the world, he lets the zombies feed on him so that they can become intelligent and aware like him. However, all that this does is turn them into Deadpools as well.

It is safe to say that in any version that Deadpool and zombies mix, the world is doomed and this might be the one situation where Slade Wilson wins against Wade Wilson.