ShikaSaku

SikaSaku is the het ship between Shikamaru Nara and Ssakura Haruno from the Naruto fandom.

Canon
Shikamaru and Sakura have known each other since they were in the academy together, while not many interactions, it seemed that the two were good with each other. In the Chunnin Exams Shikamaru and his team watch Sakura protect an unconscious Naruto and Sasuke from ninjas from the Sound, it was Shikamaru that voiced that they should help her as she was in trouble and convinced Ino to do the same, telling her that she and Sakura were friends when they were younger. During Sakura's battle with Ino, Shikamaru was impressed with her skills.

The two also deflected a genjustsu which would of made them fall asleep, Kakashi assigned Sakura to go and help Sasuke and take Naruto and Shikamaru with her. After she woke Naruto up she went over to Shikamaru but noticed his eyebrow twitch and hit him and yelled at him for trying to sleep. However he went with the two but had to stay back to hold off a ninja blocking their path.

When Shikamaru and the other boys were gathered at the gate to bring Sasuke back, Sakura came and cried to them (mainly Naruto), she noted that not even Sakura could stop Sasuke from going. Shikamaru calms her down and says her work is done and should leave everything up to him and his group, and watched as Naruto gave Sakura "the promise of a lifetime" to save Sasuke.

Somewhere during the filler arcs, it shows Shikamaru and Sakura sharing a bench together, when Naruto asks Sakura if she was dating Shikamaru, angering Sakura. Shikamaru replied that he had to give some information on some herbs to Lady Tsunade.

In Part II they are still on good terms and Sakura became a Chunnin like Shikamaru did back in their academy days. During the Hidan and Kakazu Arc when Sai and Sakura were assigned to help Shikamaru in defeating Hidan, Sakura thought to herself that Shikamaru was the smartest person in the Land of Fire.

In the Kage Summit Arc Shikamaru stood outside of Lady Tsunade's tent while Sai told Sakura of Naruto's feeling towards, looking distressed. He then entered and tells her about Konoha 11 decision to kill Sasuke themselves as it's their responsibilty because Sasuke is their former friend, he tells her that of she and Naruto go to the Raikage and they die by his village ninja's, himself along with Chouji and Ino wouldn't sit still and avenge them and that it will go in a cycle. When she tells him to stop talking he does but looks uncomfortable, when she says that she understand and wants to be the one to tell Naruto he lets her, knowing she will be better in telling him then anyone else.

During the war he is present when Sasuke makes his appearance and Team 7 make their reunion, he is also failty wounded in an attack and is kept alive by Sakura's healing abilities until Naruto helps with the Nine-Tails chakra. They were also the only people to be promoted to Jonin in the Leaf Village after the war.

Naruto the Movie: Legend of the Stone of Gelel
Shikamaru and Sakura are on a team with Naruto, together all three of them have to deliver Nerugui to its rightful owners, however when they arrive at the village where Nerugui's owners live, they are attacked by Temujin's warriors, who wield the power of the Stone of Gelel.

Naruto Shippūden the Movie: The Will of Fire
Shikamaru along with the rest of Konoha 11 have a mission to bring Sakura and Naruto back to the Leaf Village after they ran and are trying to save Kakashi from sacrificing his life to save them. They avoid him and the team but Konoha 11 tell convince Shikamaru to keep going. He tried to stop them but eventually joins them after he see's what their doing is right, he helps Sakura and Sai defeat one of Hiruko's summons. The two then watch Kakashi and Naruto have a "moment" which is interpreted as romantic, with Sakura sighing and Shikamaru saying "Oh come on, you gotta be kidding me"

Naruto the Movie: Blood Prison
They are both part of the team that save Naruto from prision, who was wrongly imprisoned, it was revealed that Sakura;s pleading at the beginning of the movie is an act which was needed.

Road to Ninja: Naruto the Movie
The two along with their classmates fight off an attack by what seems to be the entire Akatsuki roster, but what are actually disguised parts of the White Zetsu Army. When Naruto and Sakura are sent to the Genjutsu World, they meet that world's Shikamaru: he is goofy, slow-witted, and lacks the real Shikamaru's intellect. His hair is also thicker, appearing star-shaped when held in its ponytail.

Naruto The Last
The two were assigned to the team to save Hanabi and worked well together, when they are attacked by a crab Shikamaru helps Sai contain it as Sakura finishes it off with a single punch. In the novel it states that he, along with Sai, grow fear of Sakura's strength. He also told Naruto, when we woke up, that Sakura spent three days healing him and is resting, when Naruto rushes to her he and Sai leave them for their space.

Fanon
Although a small ship, ShikaSaku have quite a lot of fans, it is mainly shipped due to the two's high intelligence and how much faith they put in each other. Many fanfics see Shikamaru as a person who can calm Sakura down when she's angry and comfort her when she's dealing with Sasuke. They also work well together and care a lot about each other as Shikamaru sates that if she (along with Naruto) where killed by the Raikage's village then he would avenge her.

Fandom
Shikamaru Nara/Sakura Haruno tag on Archive of Our Own

ShikaSaku tag on Tumblr

Trivia

 * They are noted to be the smartest people in the Leaf Village.
 * They were the only ones of the Leaf Village to be promoted to Jonin after the war,
 * Shikamaru is shown to be able to hint at Sakura's future motives.