During Star Wars: Episode 9 – The Rise of Skywalker’s first trailer, there’s an unmistakable tease for series villain Emperor Palpatine, whose laugh can be heard right at the end. In addition, the character’s actor, Ian McDiarmid, made a cameo on stage at Star Wars Celebration following the trailer, instructing crew to roll the video again–and he did so in character as Palpatine. However, McDiarmid has since stated the Emperor is definitely dead.
According to Polygon, McDiarmid told fans during a separate panel interview that he only showed up on stage because he “happened to be in the area.” He continued: “so I thought I should just drop in for a laugh.”
He later recalled conversations he had with Star Wars creator George Lucas regarding Palpatine’s fate. McDiarmid said: “‘Is he…?’ And before I could even finish the sentence, [Lucas replied] ‘Dead, yes.’ ‘Well, couldn’t he perhaps…’ ‘No. He’s dead.’ ‘Well, wouldn’t it be interesting if…?’ ‘Forget it.'”
However, while Lucas created the series and directed four of its first six films, he no longer owns or controls the franchise, which now belongs to Disney. It’s since been well documented that Episodes 7, 8, and 9 do not follow what Lucas had planned, so it’s possible the franchise’s new owner may find a way to resurrect Palpatine in a late twist. There’s also Palpatine’s own hints to Anakin that there are ways to cheat death, and plenty of other ways the Emperor could return from the grave.
Source: Despite Star Wars: Episode 9 Tease, Emperor Palpatine Is “Dead,” Actor Says – GameSpot