This theory starts off with how most people see Wano as the arc for Zoro/Choppers growth, I believe one other will get an unexpected reveal and it being Luffy running into his mother.
How and why? Well let’s go to Dragon and why he would be in Wano in the first place. We know that he had something going on during Roger’s execution. I believe that something lead him to Wano. I believe he may have stumbled upon some information dealing with the Void century or the Poneglyphs in general. That lead him to go to the place that didn’t allow Government interference. Wano.
During his time there he probably had hard time getting information since he most likely snuck in do to their unwillingness to have outsiders in there lands, however he was probably starting to piece a few things together to fully realize what the Government was hiding and starting building up a small portion of his Revolutionary Army. He then finds who will later become Luffy’s mother.
This woman probably has an adventure spirit and wanted to leave the walls of Wano and explore the seas and most of all be free. Because of her status she was unable to fulfill those dreams. She met Dragon and he told her of the outside world and islands he’d been to and bit of what he was set out to do. They fell in love and she got pregnant with Luffy. She didn’t want Luffy to be stuck in the land as she was and thus had Dragon take him away Wano. Knowing the taboo of not only sneaking in and now taking out a citizen of Wano. Dragon took Luffy and the few others who he’s gather and left knowing full well they could never return the is land. Heartfelt goodbyes Luffy’s mother says bye to the both of them hopes Luffy will follow his dreams what ever they are. Dragon gets in contact with his father on Foosha Island and tells him to take care of Luffy since he can’t involve a baby in his schemes.
As a bonus, the status of Luffy’s mother could be that of cousin or sister of Momonoske, and with the blood of D. and Kozuki clan it allowed Luffy to hear the Voice of All Things, while Momonoske got the main Kozuki clan blood from father which would allow him to control Zunisha(that Luffy can only hear).
*Theory by Admrial D. Andrew