Several states are filing lawsuits to assert that the current president cannot use the same authority to cancel a Presidential Executive Order that the former president used to create the order in the first place.
Several of the suits also cite violation of the Administrative Procedure Act for failing to follow the process for notice and comments, but that is pretty shaky territory since in creating the act that they seek to overturn, the Obama administration also failed to follow those same procedures. If a court overturned Trump's cancellation of DACA on those grounds, it would also have to overturn DACA itself on the same grounds. It's called "being hoist on one's own petard." Admittedly, I'm not sure what a petard is, but being hoist upon it sounds unpleasant.
Google is your friend. A petard is a small bomb. One certainly does not want to get hoist upon one of those; one's own or anyone else's.
There were some sane heads who said at the time that the problem with Obama's whole schtick of "If Congress won't act then I will," other than the unconstitutionality of it, was that what could be done by the executive order of one president could be undone by the executive order of another president. Obama supporters seemed to think that no Republican would ever be elected to the White House, and they now seem to think that is still true, denying reality to the bitter end.