Ken Leung portrayed U.O. Statura in The Force Awakens. To my knowledge, he does not appear in The Last Jedi. Is he still alive?
It would appear that Ken Leung appearing in the The Force Awakens was because of J. J. Abrams using him as a reference to his previous work, in this case Lost.
Grunberg, who also played the pilot on the Abrams-produced Lost, is joined in the Resistance by another Lostie—KEN LEUNG, who played DHARMA spawn Miles. Here he’s Admiral Statura, a member of the rebel force set on taking down the First Order.
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With J. J. Abrams not directing The Last Jedi it's likely he may not have had a say in what actors would come back into the film. It would also appear that the actor was filming for Inhumans during a similar period to The Last Jedi so may have had a filming conflict.
In universe though U.O. Statura doesn't appear in the film and I can't find any references to him in it yet so it would appear the character is dead. Likely during the events of the film considering how many died.
It's worth noting that he isn't in the list of currently identified characters that survived to escape onto the Millennium Falcon at the end of the film pointing to him most likely being killed.
In the novelization of The Last Jedi, it says Leia sent pilots Jess Testor and Snap Wexley to find or recruit allies of the Resistance. There might have been others as well, such as this character.