Lucasfilm is developing a Star Wars TV show centered on Rogue One: A Star Wars Story character Cassian Andor, and it could possibly continue a plot point that was left unresolved from Disney XD's Star Wars Rebels animated series. One of the many things that Star Wars Rebels did for the rest of the overarching Star Wars franchise is that it fleshed out the Rebel Alliance's origins and gave meaning to the people made it what it was, before Luke Skywalker and his friends joined up with them in A New Hope.
While audiences have seen the Rebels take the Empire head-on in multiple battles over the years, on both the big and small screen, it hadn't been thoroughly explored outside of Star Wars Legends how the Rebels were able to gather their intelligence on the Imperials. One of the best things that Star Wars Rebels did in that regard was that it introduced the code-name Fulcrum - a title used by multiple Rebel informants, some of whom were former Imperial officers. It ended up becoming Lucasfilm's Star Wars version of the Culper Ring.
In the aftermath of Order 66, Ahsoka Tano became the first Fulcrum operative and helped inform Bail Organa, as well as the rest of the early Rebel leaders, about the Empire's plans. She was later replaced by Alexsandr Kallus, a former Imperial agent who was originally tasked with hunting down the crew of Star Wars Rebels' Ghost. While they were the only two people who went by Fulcrum in the TV show, it was later revealed that Cassian Andor was also once Fulcrum.
With Lucasfilm bringing back Diego Luna as Cassian Andor for a live-action Star Wars TV show on Disney's upcoming streaming service, Disney Plus, this presents the perfect opportunity to explore Cassian's origins in the Rebel Alliance as well as his time operating as a Rebel spy. In Rogue One: A Star Wars Story, Cassian tells Jyn Erso (Felicity Jones) that he had done terrible things in the name of the Alliance, and so had many others. Being a spy could require someone to perform heinous acts, so having at least one season dedicated to Cassian's time as Fulcrum would be ideal.
Furthermore, considering that Rogue One: A Star Wars Story was the first movie to bring a character from The Clone Wars TV show - Saw Gerrera (Forest Whitaker), specifically - into live-action, it would be fitting for Cassian Andor's Star Wars TV show to continue that tradition to adapting characters and storylines from animated projects. But this is something that audiences will just have to wait and see what happens.