Internment was a bit complicated, but my understanding is that the US army wouldn't turn away young Japanese-American men who were willing to fight in Europe.
There was also a secret program where second generation men served as translators for US naval intelligence in the Pacific. They translated intercepted messages and assisted with prisoner interrogations. They were also in very real danger of being mistaken by the enemy by US or allied troops. The existence of this program was only revealed in the 1980s. If anyone is interested, google "Nisei linguists" or check out these references
Internment was a bit complicated, but my understanding is that the US army wouldn’t turn away young Japanese-American men who were willing to fight in Europe.
Japanese-Americans (and Korean-Americans as 'enemy nationals') largely served in segregated units during the war, unlike other Asian-Americans.