So, it seems we'll have to wait a while for the Disney Plus streaming TV series following Diego Luna as Rebel spy Cassian Andor in the timeframe before "Rogue One", as TheForce.net reports that filming is scheduled to begin in October of 2019. As the series will most likely involve grand production design and complex special effects, post-production will probably take some time as well, meaning that we might not get to watch the series until at the earliest, late summer or fall of 2020.
From StarWars.com...
"The series follows the adventures of rebel spy Cassian Andor during the formative years of the Rebellion and prior to the events of Rogue One: A Star Wars Story. The rousing spy thriller will explore tales filled with espionage and daring missions to restore hope to a galaxy in the grip of a ruthless Empire."
However, we'll have plenty to tide us over until then: "Star Wars: Resistance" resumes in January, Jon Favreau's Disney Plus series "The Mandalorian" is currently filming and expected to debut by late 2019 or early 2020 at the latest, and "Star Wars: Episode IX" comes out in just under a year.