Star Wars: The Bad Batch has released its full trailer online, and it confirms that two characters from Star Wars: The Clone Wars will be showing up in The Bad Batch. The first returning character is Saw Gerrera, the infamous resistance fighter from Onderon. Gerrera has become a bigger and bigger through-line for the Star Wars franchise, showing up in Clone Wars, Rogue One, and now The Bad Batch. The other returning character is Captain Rex, the Clone Trooper leader who escaped the brainwashing of Order 66 being one of the few clones to have his implant removed.
Captain Rex was last seen in the final scene of Clone Wars, escaping into hiding along with Ahsoka Tano. Ahsoka will be getting her own solo series that will hopefully delve into her life during those turbulent times of the Empire's rise - but it looks like Rex's story will get a needed gap-fill with this cameo in The Bad Batch. Rex showed up in Star Wars Rebels, which is set years after The Bad Batch, having found life in solitude with a few of his clone troopers. Now we'll get to see some more insight into how he reached that place.
Saw Gerrera was trained by Obi-Wan Kenobi, Anakin Skywalker, Ahsoka Tano, and Rex during the Clone Wars, as The Republic indirectly aided Onderon in the fight against the Separatists Droid Army. However, because The Republic never directly aided him (and the war cost his sister's life), Saw began down the path of an independent guerilla revolutionary. We already know that path leads to the planet Jedha, where Saw at the forefront of the extremist wing of The Rebellion during the pivotal mission to stop the Death Star (Rogue One). The Bad Batch trailer seems to tease an arc where Clone Force 99 will have to confront the moral line of fighting against the Empire, at the moment where Saw really starts to embrace his hardline tactics.
Also returning for The Bad Batch is Fennec Shand (Ming-Na Wen), the famed assassin who eventually ends up hunting down The Mandalorian Din Djarin and Baby Yoda (Grogu). Like Saw Gerrera, Fennec has a growing arc in the Skywalker Saga; at the end of The Mandalorian season 2 she flipped sides and helped Djarin fight off the Imperial remnants, and is now allied with Boba Fett to take over the Outer Rim underworld, after the power vacuums created by the death of Jabba the Hutt and the Empire's fall.