At the end of Resident Evil 6, King Ada gave Leon a ring?

No, it was a ring given in the game as an underground entrance prop of the Simons family, which seems to be a symbolic prop of the Simons family.

At the end of the game, a short message was sent to Lyon's mobile phone, saying that Lyon is cute or something.

For details, please refer to/video/3628.html. Here is a story video of Resident Evil 6LA summarized by others, and there are also some ending videos.