In the mine in Solo, Chewbacca meets some other Wookiees. Are they from his family/tribe?
I assume from the Star Wars Christmas Special (which is still canon in my mind) which is set after the events of Solo that Chewie has his family back.
According to the film's official novelisation they're just random enslaved Wookiees.
Chewie gave a roar of rage, seeing more Wookiees fall to the mobilizing sentinels. “Do you know them?” Han asked, uncertain.
Chewie gave him a withering look and a moan.
“Well I didn’t know,” he muttered. “I know they’re your people but we have a job to do. Remember, the plan?”
The elder wookiee Sagwa later confirms that these are not even Chewie's tribe.
Sagwa pointed into the fray. Our tribe has procured a shuttle. They’re waiting for us to go home.
They aren't related or atleast not closely, but they do both come from the same city on kashykk, so hypothetically they could have a shared ancestor some generations back.
That Chewbacca is a father and has a family is reintroduced as canon in Chuck Wendigo's Star Wars: Aftermath series, specifically in the 2nd book of the series Life Debt. The book also established Chewbacca's Life Debt to Han Solo as canon and it also establishes that the Life Debt extends to members of Solo's family, however the Life Debt is not explicitly mentioned in Solo: A Star Wars Story despite the fact that the events that led to Chewie owing Han a life debt clearly happen on screen in the movie. The novel mentions the event vaguely enough that it could be retconned if need be and the film offers no clarity on the issue.
My point is, wookiees do not pledge their life to someone on a whim and Han Solo never saves Chewbacca from slavery/captivity in the films, it is reasonable to conclude that Chewie pledges his life to Solo not because he saves Chewie but because Han Solo helps Chewbacca track down his family or at least it's because he helps him save other wookiees.
There's some details in the the film that point in this direction, for one until after we get to Kessel it is very clear that Han and Chewie are not honor bound, there's no life debt in place, as far as Han and Chewie are concerned Chewie can come and go as he pleases.
In fact, when they get to Kessel Chewie does exactly that. When Chewbacca sees another wookiee who is enslaved he doesn't think twice about abandoning the mission. He completely takes off, even at the risk of being permanently separated from the Falcon crew, to rescue that other wookiee.
Of course Chewbacca and his new(?) wookiee friend return and help with the mission, and it is never established exactly who this other wookiee is to Chewbacca, if they are old friends, or if the wookiee is a member of Chewie's immediately family even his child...it's not stated. It's open ended and we don't know. But what we do know that they share a warm embrace and touch eachother's forheads together in a way that communicates a very personal or symbolic gesture.
And we know that after the mine heist Han and Chewie grow closer, Han doesn't even know that Chewbacca is a really great co-pilot or his age until after the heist and it's certainly not a mistake in the film that the Han and Chewie dynamic we know and love comes into play after they leave Kessel.
So, there's nothing conclusive but it is a very reasonable conclusion that Chewie is related to the wookiee they find on Kashyyyk. If not, at the very least they're not complete strangers Chewie isn't exactly an unknown among his people but as we see in Revenge of the Sith he once servds directly at the side of the wookiee Chieftain.