Emoji have a diversity problem, but it looks like Apple and Google are on the way to fixing it. Emoji are all standardized by the Unicode Consortium, and the consortium this week is publishing a new proposal for how emoji should be displayed that includes support for different skin tones. The proposal was edited by Apple and Google engineers, and though the diverse emoji are still part of a proposal, they're planned for inclusion in the next major update to the Unicode standard, which is scheduled for the middle of next year.
Emoji diversity would work by allowing people to modify characters with a number of different skin-tone swatches. When placed side-by-side, a face and a skin-tone swatch would combine into a face with that skin tone. The consortium is proposing support for five different skin tones which would be supported, at a minimum, by most of the human emoji. The proposal also says that support could optionally be extended to the smiley faces, hand symbols, and other body parts. No other emoji would respond to color changes, despite how fun that might become.
The diversity issue with emoji has been fairly obvious for a while now, but it's been a growing issue as emoji have grown in importance for communications. Apple even stated earlier this year that it felt "there needs to be more diversity in the emoji character set," noting that it was working with the consortium to update the standard.
Given that this proposal comes from one Apple engineer and one Google engineer, who also happens to be president of the consortium, it's pretty clear that this is a real issue that tech companies want to address. Though those two companies are the only ones listed with an involvement in this proposal, the overall standard is widely supported — so any modern platform that you're using emoji on right now has a good chance of supporting diverse emoji sometime after the standard is finished.