Intelligent Design is a re-branding of old earth creationism. Religious groups in the US tried for decades to get Christian creationism taught in American science classes but were repeatedly defeated by the US courts because, according to the scientific community, creationism isn’t a scientific viewpoint.
In response old earth creationists began replacing the terms for a religious version of god with “intelligent designer” and attempted to reword the standard creationist arguments with more scientific sounding terms in an attempt to conceal their religious origins and agenda.
While embracing the new term, old earth creationists continue to make the same traditional claims that certain levels of complexity are impossible to naturally occur, without being able to verify the assertion. Whether creationists will one day discover a way to verify such an assertion remains to be seen.
Intelligent Design creationism is essentially the offspring of centuries of god of the gaps theology, in which religious believers credit their deity with having supernaturally created whatever thing the current scientific community didn’t have a full and compelling explanation for.