Because without altering any continuities, if Fox's Wolverine and Marvel's Captain America were to come to blows, the claws would slice through the shield like a hot knife through butter. Vibranium can absorb kinetic energy, but it isn't indestructible (as evidenced by Thanos destroying the shield in Endgame).
BP's vibranium is stated to be woven strands, and that weaving is supposedly able to be pierced along the weave in ways it would not be if slashed/pierced across it or subject to blunt force. With the right angle, then, Wolverine could absolutely pierce BP's armor.
In Age of Ultron, concentrated energy blasts of sufficient heat and power are also shown to be effective against Vibranium. Thor's lightning, Vision's Mind Stone lasers and Iron Man's repulsor beams were able to melt Ultron's body when used in combination, meaning that high enough temperatures can break Vibranium down.
His claws have also failed to cut or pierce the mangog, the nemean lion, the juggernaut, king thor in the reigning, and celestial armour. Basically his claws cannot cut through any material, being, or object which is stronger or tougher than primary adamantium.
His adamantium claws are one of the few weapons in the Marvel Universe that can consistently pierce Hulk's skin and Wolverine has no problem going for Hulk's head. In fact, if it came down to it, Wolverine could cut Hulk's head off, ending the Hulk once and for all.
Both mutants are ostensibly on the same side; they differ greatly in temperament but are not afraid to fight for mutants against a world that hates them. While Colossus uses his brute strength, Wolverine uses his claws, which can cut through almost anything - except Colossus himself.
Can the Hulk break Vibranium? Dr. Bruce Banner discovered that during a previous Chitauri attack, the Hulk had been able to smash through the Vibranium plated Chitauri ships without any effort. Because of this, he discovered that Vibranium turns brittle when exposed to gamma radiation.
Although vibranium is susceptible to damage, it's depicted as the most durable material in the Marvel Cinematic Universe. The fact that Thanos possesses enough power to beak vibranium is a testament to the strength of the Mad Titan, but more importantly, the weapon itself.
Throughout Marvel Comics, the Hulk has tried and failed to break Captain America's shield but has never even come close, and since Superman is only a little bit stronger than the Hulk in his base form, it makes sense that Superman wouldn't be able to break the shield either.
The ability of Adamantium to pierce Hulk's hide has changed over time, but currently it can, though it requires a decent amount of force for it to cut him, as shown in Immortal Hulk #8. Adamantium can cut Hulk's skin, it just isn't all that easy.
Because without altering any continuities, if Fox's Wolverine and Marvel's Captain America were to come to blows, the claws would slice through the shield like a hot knife through butter. Vibranium can absorb kinetic energy, but it isn't indestructible (as evidenced by Thanos destroying the shield in Endgame).
Wolverine isn't just armed with enhanced senses and an impressive healing factor - his skeleton is also encased completely in adamantium. His claws are sheathed in the metal, allowing them to be razor-sharp and could certainly cut through Iron Man's armor.
With only four exceptions, Wolverine would never be able to cut through Superman skin, with his adamantium claws. Those exceptions being: Superman was mostly drained of his stored energy. Superman was exposed to red solar energy.
At the end of the day, Wolverine could defeat Captain America if they were pitted against one another on multiple occasions. Sure, Cap has the will to keep going even when at the end of his rope, but so does Logan. Both are outrageously stubborn and forceful.
While Thor is easily the more powerful of the two, he finds himself incapable of matching Wolverine's speed and agility. The mutant is able to get in several swipes at the Asgardian - drawing blood - and even goes full leapfrog on him, impaling him through the back with all six adamantium claws.
Mjolnir doesn't damage Cap's shield at all, as shown below. I think it is fairly safe to assume that Stormbreaker (being a cutting weapon, rather than Mjolnir which is designed to smash or build) would inflict similar damage to the shield as Thanos sword does. Conclusion: Stormbreaker minces Cap's shield.
Many viewers have pointed out that Thanos was able to lift Stormbreaker without a problem, but this is because the ax isn't enchanted as Mjolnir is. Others believe Thanos lifted Mjolnir (although briefly) and have even argued that he would be worthy of doing so.
Physically they're pretty evenly matched, but Thanos is just a much more skilled fighter. No stones were used in the fight. Per Joe Russo: "I would say that he's just that powerful," said Joe Russo.
Hulk's inability to break Wolverine and his adamantium claws isn't an indictment of the green monster's strength but more shows how strong Wolverine's metal-coated bones really are.
Fearing for their safety, Spidey hit the Hulk with all of his strength, and sent him flying up… and up… and up. The next thing the Hulk knew, he was orbiting the Earth like a satellite.
Wolverine's vaunted claws can cut the Hulk's skin, but they can't do diddly-squat to the Juggernaut. Wolverine can't hurt the Juggernaut, but the Juggernaut sure as Hell can hurt Wolverine.
So while Juggernaut is much more powerful, and would normally be able to win in a fight, Colossus could convince Cyttorak to transfer his power, or even cut off Cain Marko's connection to Cyttorak. Cain Marko would be left as a normal human. Colossus would still be a powerful mutant.
The general consensus was that Wolverine's claws could theoretically puncture Superman's skin, but that it would require tremendous super strength behind them to do so, which Wolverine doesn't have.
