LEDs made small enough to serve as pixels in a display, or as a backlight for an LCD display with high-resolution local dimming.
Large LCDs for home televisions, etc. have long offered LED backlights with local dimming for better contrast, but this technology is difficult to shrink to the small, thin LCD panels used in mobile devices. microLED technology (using very tiny white LEDs) makes this possible for the first time.
There are also companies working on displays made exclusively of microLEDs, using very tiny red, green, and blue LEDs as individual pixels. These are similar to OLED displays in design and advantages, including high contrast and flexible panels. But microLED displays can be brighter and more efficient than OLED displays.