A simple plot could be that they are invited to join as a sign of a new era of cooperation. Naruto and Sasuke accept and immediately start to work on improving relations. They hold joint training sessions for the ninjas of both villages, which helps in building trust and camaraderie.
One possibility could be that Naruto and Sasuke, with their newfound understanding and power, decide to bridge the gap between Konoha and Suna. They might start by sharing their unique skills and knowledge. For example, Naruto could teach Suna ninjas about his shadow clone jutsu, while Sasuke could offer insights on advanced chakra control. This would lead to a stronger alliance between the two villages, with the two heroes becoming symbols of unity.
One reason could be a special mission. For example, there might be a threat that only Naruto can help with in Suna. Maybe there's a new type of enemy that has some connection to Suna's unique chakra sources and Naruto's abilities are needed to figure it out.
Well, one possible plot could be that they join initially to spy on Akatsuki from the inside. Naruto might think he can change the Akatsuki members' minds with his talk - no - jutsu. Sasuke could be there to find out more about the secrets Akatsuki is hiding, especially those related to his family. Maybe they end up causing chaos within Akatsuki as they slowly turn some of the members towards a more positive path.
One plot twist could be that they find out a traitor in Suna who is secretly working for an enemy of both Konoha and Suna. This would put them in a difficult situation as they have to figure out who to trust.
One possible plot development could be Naruto leaving to find a way to prevent Sasuke from ever wanting to leave in the first place. He might embark on a journey to discover the root cause of Sasuke's hatred and try to resolve it from afar. This could lead to Naruto meeting new characters who have insights into the Uchiha clan's past and Sasuke's state of mind.
One possible plot twist could be that they are being secretly manipulated by an unknown enemy who wants them out of Konoha for some dark purpose. Maybe this enemy has spread false rumors about them in the village, making them feel like they have no choice but to leave. Another plot twist might be that they discover a long - hidden truth about their families that is connected to some ancient power outside of Konoha, which compels them to leave in search of answers.
One possible plot could be that they leave Konoha due to a new threat that the village is unable or unwilling to face. They might go on a journey to find a way to defeat this threat on their own. Along the way, they could face many challenges that test their friendship and skills.
A plot twist could be that Akatsuki has a hidden agenda that Naruto, Sasuke and Sakura are unaware of when they join. Maybe Akatsuki is being controlled by an even more powerful and sinister force, and the three are lured in as pawns. They then have to figure out the real situation and fight not only against the Akatsuki members who oppose their reform ideas but also against this hidden power.
Maybe Naruto leaves to Suna because he has some personal issues in Konoha. He could be seeking a fresh start in Suna. There, he might meet new friends and foes alike. He could get involved in Suna's internal politics or power struggles while trying to prove himself as a valuable ally.
Well, in a 'naruto lives in suna' fanfiction, perhaps Naruto is exiled from Konoha for some reason. He then finds a new home in Suna. He starts training with the Sand ninjas and discovers new aspects of his chakra control. He also gets involved in the internal politics of Suna, trying to bring peace between different factions within the village.