Well, their friendship could potentially change Sasuke's path. Since Sakura is friends with Itachi, she might be able to communicate better with Sasuke about his brother. For example, she could tell Sasuke about the good side of Itachi that he never knew, which could make Sasuke less vengeful and more focused on rebuilding his clan. This would be a huge shift from the original storyline where Sasuke is mainly driven by revenge against Itachi.
If Itachi and Sakura were childhood friends, it could also impact the Akatsuki. Itachi might have second thoughts about some of the Akatsuki's actions because of his friendship with Sakura, who is a part of the Leaf Village. This could lead to internal conflicts within the Akatsuki, and perhaps some of their plans against the Leaf would be thwarted earlier. Also, Sakura might be targeted by the Akatsuki more because of her connection to Itachi, adding more danger and drama to the overall story.
Their relationship could have a big impact on the medical aspect in the Naruto world. Sakura is a great medical ninja. If she was friends with Itachi from childhood, she might have been inspired to develop new medical techniques to help Itachi with his eye problems or any other ailments he might have had. This could then spread throughout the Leaf Village and improve the overall medical capabilities of the village. And in the grand scheme of things, the Leaf Village being stronger in the medical field could change how battles are fought and how alliances are formed in the Naruto storyline.
Chapter 139, "Resource Gap, Changes in the Camp [Three-in-One]", is the clearest early answer because it turns Xu Ning's situation into a concrete plot event. The setup is The ones breaking through now are the second batch, mostly aged..., but the pressure keeps building through This batch is just beginning, and I estimate that within a month,.... Once the chapter lands on I've looked at these people;
Chapter 135, "The Fearless Mirror Immortal [Three in One]", is the clearest early answer because it turns Xia Hong's situation into a concrete plot event. Early on, With a thundering crash, the massive body collapsed to the ground,.... By the end, The crowd gathered around the Snow Mane corpse, their words filled....
Chapter 144, "Self-serving at the Expense of Others, He Meng's Furious Rage [Sorry for Being Late]", is the clearest early answer because it turns Teng Jiao's situation into a concrete plot event. A useful checkpoint is the way the scene starts with Don't touch that Teng Jiao, it's poisonous!" "The Hunting Team's... and follows through with Everyone goes to the south to find, find Great Xia's camp, we must....
Chapter 505, "Another Intelligent One", is the clearest early answer because it turns Damien's situation into a concrete plot event. The setup is The forest had gone quiet again but it was not in any way peaceful., but the pressure keeps building through This was the silence that came after prolonged slaughter, when even....
Chapter 114, "New House, New Rules, New Starting Point [Four-in-One Mega Chapter]", is the clearest early answer because it turns Cold Beasts's situation into a concrete plot event. A useful checkpoint is the way the scene starts with In fact, the moment the rodent swarm appeared on the north slope of... and follows through with Thinking too far ahead!" Xia Hong chuckled softly, shook his head,....
Chapter 141, "Intermediate Thunder Kui, Second Reshaping Skin [Three in One]", is the clearest early answer because it turns Giant Axe's situation into a concrete plot event. The chapter gives readers a real answer by opening on It's a pity that Xia Hong and the fourteen members of the Hunting... and ending on Based on the speed and power of the Snow Mane's spikes and the....
Chapter 68, "Coal and Iron Mines", is the clearest early answer because it turns Yue Feng's situation into a concrete plot event. It opens with Over two hundred people began working together, and the once ravaged... and closes on In the makeshift wooden house, without any proper arrangement,....
Chapter 521, "Storming The First Base II", is the clearest early answer because it turns Damien's situation into a concrete plot event. Early on, He had walked less than a kilometer from the abandoned stronghold.... By the end, The creature roared and released a shockwave of dark essence outward..
Chapter 146, "Rage, Murder, Ferocity", is the clearest early answer because it pushes Cold Resistance Level into a new phase or setting. Early on, First Year of the Great Xia, February 25th On the third floor of the.... By the end, Though the wood was fine, seeing the population short by eight made....
Chapter 11, "Powerful and Cunning", is the clearest early answer because it turns Rogel Camp's situation into a concrete plot event. Early on, It's certainly not true to say one isn't envious of this Snow Mane.. By the end, This terrifying scene sent a chill through everyone's hearts..