According to endosymbiosis, what is the best explanation about how eukaryotic cells evolved? Bacteria that were capable of photosynthesis engulfed smaller, heterotrophic bacteria.
Cells that did not fully separate during cellular division fused, forming larger organisms.
Chloroplasts and mitochondria were once prokaryotes that began to live within larger cells.
Two or more prokaryotes fused to form larger, multicellular organisms.

The analogy says that stem cells were important for medicine, just as the internet was important for communication, because if you look, thanks to the internet, different social networks and different media have emerged. Nowadays it helps a lot of people in different cases, like online classes for certain schools. Without the internet, people would still be talking in person, and in these quarantine times it would not be possible. And the internet also made it possible for strangers to connect, making multiple communities.

I hope I helped, even speaking only on the technology side.