When you look at Star Wars: The Force Awakens and Star Wars: The Last Jedi side-by-side, you start to see what the filmmakers had in mind for the structure: have each movie shine a spotlight on a protagonist from the original movies and conclude their story in a meaningful way.
When you consider how the most recently trilogy of Star Wars movies has operated to this point, the inclusion of Lando Calrissian in the third chapter is an interesting move.
The Force Awakens is a goodbye to Han Solo, The Last Jedi is a goodbye to Luke Skywalker… and Episode IX presumably would have been a goodbye to General nee Princess Leia.
Sadly all those plans had to change with the untimely passing of Carrie Fisher, so this situation makes one wonder if Lando might be getting the same kind of legacy treatment in her place (while presumably honoring Leia in a different way).