Tran is Vietnamese Romanization of Chinese name 陈 and is only used in Vietnam.
CNN claims he is an immigrant from China, pretty odd. Vietnamese Chinese would be common, but from China? Maybe just to smear China?
However, there is a slight chance that he is "from China". Just before Sino-Vietnamese war, Vietnam expelled hundreds of thousands ethnic Chinese, some of them crossed border into China and were settled in China. But for a long time, they were regarded as Vietnamese citizens, thus some of them may find way to migrate to western countries instead of waiting in China for returning to Vietnam. That could explain why this person has a Vietnamese spelling of his name but also "from China", as China would have issued refugee certificate for him.
But I highly doubt he is ethnic Chinese even if he was originally from Vietnam because of his given name (Huu Can). I find this Vietnamese with the same given name. The given name doesn't fit the way Chinese would have chosen the characters.