Lead You Can Relate To

Often in media, the creator wants to tell a story about people who aren't like the majority of the target audience, but worries that said audience won't be able to relate to those different people. So they will put in a protagonist or point of view character who is like the presumed audience, and therefore "relatable." The hope is that the audience will then transfer their ability to care for the protagonist to the group of people the story is actually about.

In a mainstream Hollywood film, for example, the protagonist is likely to be a White Male Lead who's middle-class, heterosexual, cisgendered and able-bodied, while the majority of the characters are anything but those categories. A film aimed primarily at black people would substitute "black" for "white", a Japanese film would have a Japanese person as the point of view character, and so forth. Sometimes this can be stretched a bit; a mainstream Hollywood film might have a middle-class able-bodied black man as the protagonist in a story about wheelchair-bound urban youth, for example.

While this storytelling device is often used in situations involving race or ethnicity, it is not confined to those by any means.

Usually, the audience-like character has their own subplot within the story, overcoming their prejudice or romancing a member of the unlike-audience group. If handled poorly, this can become a Plot Tumor that takes time away from the film's supposed focus story.

Now, this can be a good thing in moderation. It's true that many people relate better to a protagonist/point of view character they can identify with on some level. But it can also come across as insulting both to the target audience (if the story assumes the audience knows absolutely nothing about the outside group) or to members of the outside group (suggesting that that group would not be able to handle their own problems without the intervention of an in-group person, especially aggravating if the POV character is either completely made up or a "normalized version" of an outside group member.)

Common subtropes of this are Foreign Correspondent, where a person from "our country" goes to "their country" and gets involved in local affairs and issues, White Man's Burden, in which the protagonist (usually white) works to uplift disadvantaged people of the outside group, and Black Like Me, in which a member of the audience's group goes undercover as a member of a different group to discover what life is like for the other group. Examples that are purely one of these subtropes should go on those pages.

Compare Audience Surrogate, where one character is designated to ask the sort of questions the audience would logically be asking during the story; and Escapist Character, where the protagonist differs from the audience, but in positive, wish-fulfilling ways that the presumed audience finds relatable.

Contrast Mighty Whitey, in which a person from the presumed audience's culture goes somewhere and is better at what the natives are good at than the natives themselves, and Exotic Backdrop Setting which is what happens when someone from the audience's culture goes somewhere, and the exotic people/culture there only serves as a backdrop to the protagonist's actions, with local affairs and issues largely irrelevant to the plot.

Examples of Lead You Can Relate To include:

Anime and Manga

Real: While the later manga volumes widen to focus to be more about the team members themselves, the initial viewpoint character is an able-bodied high school dropout who becomes involved with the world of wheelchair basketball after a chance encounter. Also has a parallel storyline about a "normal" athlete becoming handicapped and having to learn about being in a wheelchair.

Film

The Last Samurai: An American army officer is sent to Japan to modernize their military and comes to admire samurai culture. (In Real Life, the equivalent person was French, but the movie was made for Americans.)
The Help: A white woman interviews black women working as maids in the Deep South in The Sixties and becomes involved with their personal lives and struggles.
Blind Side: The story of a young black man who overcame poverty to become a successful professional football player—told from the perspective of the white family that helped him.
Rain Man is purportedly about autistic Raymond, but is told from the POV of his non-autistic brother.
Red Tails notably averts this trope; George Lucas had trouble getting funding for years because he had the radical notion that a film about the heroic Tuskegee Airmen should be about the Tuskegee Airmen being heroic, rather than the noble but conflicted white officer who teaches them how to be heroic.
Dances with Wolves tells of the plight of Native Americans through a white male lead.
The Ramen Girl: An American woman is stranded in Tokyo after breaking up with her boyfriend. She ends up in a ramen shop.
Many documentaries use this device: the interviewer or narrator is from the audience's culture, introducing and examining the lives of more "exotic" people.

Literature

A Walk with Ian, a children's book about a non-autistic girl named Julia taking a walk with her autistic brother Ian.
The book One Flew Over the Cuckoo's Nest is an inversion. The story is about how a "normal" person changes the lives of a group of mentally disturbed people, but the point of view character and Unreliable Narrator is one of the group being affected. The Film of the Book uses this storytelling device straight.

Live Action TV

The Tyra Banks Show: Tyra would often disguise herself and go undercover for a day to see what life was like for non-supermodels. She put on a Fat Suit, she dressed as a man, she went homeless, and was a stripper.

Visual Novel

Katawa Shoujo: A "normal" boy develops an "invisible" physical handicap and must attend a school for the physically disabled, learning about their issues and struggles.

Web Original

Examined in this Cracked.com article, specifically the item titled, "Sci-Fi Needs a Straight Man Like a Laurel and Hardy Routine".

Western Animation

Hey Arnold!! episode, "Rhonda's Glasses," Rhonda, the most popular girl in school, becomes a geek after getting glasses and explores the geek world.