One possible plot could be that Naruto goes to Kumo but is not well - received there. Maybe the people of Kumo are still suspicious of him because of his status as a Jinchuuriki. They could isolate him, and Naruto has to struggle to prove himself worthy of their trust. He might also face discrimination from some of the Kumo ninja.
Another possibility is that there is a rogue ninja in Kumo who uses Naruto's neglected state to his advantage. He might try to manipulate Naruto into doing things that would be bad for both Naruto and Kumo, all while remaining in the shadows and making it seem like Naruto is acting on his own accord.
Maybe in the fanfiction, Naruto neglected Kumo because he was too focused on his own village's problems. But then something major happens in Kumo, like a powerful enemy targets them. Naruto realizes his mistake and goes to Kumo to make amends. He teams up with the Kumo shinobi, and they work together to fend off the threat. Along the way, he learns about Kumo's unique culture and forms strong bonds with their ninja.
Well, it could be that Naruto, feeling neglected in his own village, decides to seek a new start in Kumo. Maybe he meets some unique characters there who accept him for who he is and he begins to train in their style of jutsu, thus becoming a stronger shinobi in a new environment.
One possible plot development could be that Naruto's friends in Konoha realize he's missing and start a search mission. They might suspect Kumo immediately due to the history of tensions between the two villages. Meanwhile, in Kumo, Naruto could be held in a secret location. Some in Kumo might want to use him as a bargaining chip against Konoha, while others might see his potential and try to turn him into an asset for Kumo.
One possible plot twist could be that Naruto discovers a secret connection between his family and someone in Kumo. This could completely change his understanding of his past and future.
Well, in Kumo, Naruto might face challenges related to power struggles. There could be certain groups or individuals in Kumo who see Naruto as a threat to their own influence. He's a powerful ninja from Konoha, and some in Kumo might not want him to gain too much power or popularity there. Another biggie is making new friends. It's not easy to break into an established social circle in a new village, and Naruto might find it hard to find people he can really trust and rely on.
The Kumo ninja would likely be angry at first. They'd feel that Naruto, as a symbol of hope in the shinobi world, should have noticed their problems. But some of them might also be hopeful that Naruto's arrival would finally change things for the better. As for Naruto himself, he'd probably be shocked to realize how much he'd overlooked Kumo and would feel a sense of guilt.
In some fanfictions, Naruto might face new challenges in Kumo. He could encounter different ninja with unique jutsus. Maybe he has to prove himself all over again in this new village environment.
Naruto might become more cautious. After being kidnapped, he realizes the world is more dangerous than he thought. He could start to be less impulsive and think more before acting.
He might meet a young and idealistic ninja in Kumo. This ninja could show Naruto a different way of looking at the ninja world. Maybe this Kumo ninja has a more peaceful approach to resolving conflicts, which makes Naruto re - evaluate his own views on fighting and rivalry between villages.