The immediate cause of death is unknown.

造成死亡的直接原因不明。

《牛津词典》

Though the immediate cause of death in a startup tends to be running out of money, the underlying cause is usually lack of focus.

新生企业走向死亡，其表层原因是缺乏资金，其实深层原因是他们失去焦点。

youdao

Heart failure was the immediate cause of his death.

心力衰弱是他死亡的直接原因。

youdao

"The immediate cause of death is attributed to drowning associated with neck trauma, and the manner of death will be listed as accidental, " said a Los Angeles coroners' spokesman.

BBC: Shatner's wife died while 'drunk'