Kashyyyk was the homeworld of the Wookiee race.
Near the end of the clone wars, the wookiees, with the help of republic clones and Jedi,
were forced to repel a massive separatist invasion force.
During the battle, Order 66 was issued and the clones stationed on the planet turned
on their Jedi leaders.
So what happened to Kashyyyk and the Wookiees on it afterwards?
In Canon, shortly after the clones attacked the Jedi, the battle came to an end when the
the droid army was shut down from Mustafar.
Unfortunately for the Wookiees, the conflict didn’t end for them, as right after the
droids were shut down, the remaining clones took control of the planet.
When the new Empire solidified its control over the Galaxy, it legalized slavery on certain
alien species, including Wookiees.
Thus as a result, the Wookiees were all turned into slaves, even the children.
They were forced to cut down their sacred trees for lumber and were taken from their
planet to work on Imperial super weapons, like the Death Star.
Others even less fortunate were used as test subjects for chemical weapons.
At some point, an Imperial Holonet reported that there was a Wookiee uprising, but it
was brought down by Imperial Forces with ease.
A few years before the battle of Endor, there was a massacre on a Wookiee population on
Kashyyyk.
This massacre was so brutal, that it convinced Mon Mothma that there was no negotiating with
the Empire and that only force would be able to end its tyranny over the Galaxy.
After the battle of Endor, with the death of the Emperor, the remaining empire went
into turmoil, causing many worlds under its control to be locked down, including Kashyyyk.
This lockdown caused supply shortages on the Wookiee planet.
Despite knowing this, the emerged New Republic refused to run supply missions to the planet,
forcing Han Solo and Chewbacca to undergo the mission themselves.
They created a coalition formed from Wookiee refugees and mercenaries, and together they
were able to successfully run supply missions.
Eventually the New Republic would act, and it liberated Kashyyyk from the Empire.
And that’s how far the story goes for Kashyyyk in Canon.
In Legends, a similar end to the battle of Kashyyyk happened, with the battle ending
when the droids were shut down and the clones taking over the planet afterwards.
Under the rule of the Galactic Empire, Kashyyyk became a common sanctuary for surviving Jedi.
A group of Jedi tried to escape to Kashyyyk, but they were tracked down and brought the
full Imperial military might with them.
Groups of Wookiees saw this as an opportunity to rebel against the empire, so they aided
the Jedi against the Imperial forces.
But they were all defeated, resulting in the destruction of many Wookiee cities.
Those that survived the battle, were captured and turned into slaves to be used to construct
the Death Star.
Not even a year after this first battle, the Empire would return once again after news
of Jedi Knight Kento Marek being aided by the Wookiees.
Another battle ensued, this time against another Wookiee population on the planet, a population
that was far more well equipped than the last.
Although the wookiees were able to inflict serious casualties for the Imperial forces,
they ultimately lost and the Jedi knight they were protecting was killed, along with his
son being kidnapped by Darth Vader to be trained as a secret apprentice.
Possibly as a way to punish the Wookiees for their costly uprisings, the Empire allowed
Trandoshan slavers to enslave Wookiees for their personal means.
The empire also installed a sadistic Imperial captain to supervisor slave projects on the
planet, who would frequently hunt the Wookiees for his own pleasure.
About a year after the destruction of the first death star, a blockade was implemented
on Kashyyyk.
Darth Vader also ordered a strict curfew on the remaining Wookiee populations as a way
to squeeze out any rebels on the planet.
After the battle of Endor, Kashyyyk was eventually liberated by the New Republic and soon it
became an important member of the new galactic government.
About 35 years later, Kashyyyk saw conflict once again after it aligned itself with the
Jedi against Darth Caedus, resulting in an invasion to take place on the planet.
This time though, the Jedi and the wookiees were able to repel the invasion.
Almost 100 years after that, the newly emerged Darth Krayt's Galactic Empire viewed the Wookiees
as a threat.
But instead of enslaving them like the previous galactic empire did, they decided to completely
blockade the planet from the rest of the galaxy, isolating the wookiees in process.
Although they allowed supplies and trade on Kashyyyk, they made it very clear that the
wookiees could not leave or be informed about what was happening in the galaxy.
This allowed the new empire to keep the wookiees in check, without having to deal with costly
revolts.
And that's how far the story goes for Kashyyyk in Legends.