Dependent origination does a specific piece of cosmological work that many theistic traditions assign to a creator: it explains why there is a world of change and suffering at all without requiring any first, uncaused cause standing outside the causal chain, since on this account asking what caused the very first link is a malformed question, there being no first link, only a beginningless cycle that can nonetheless be brought to an end by disrupting its conditions here and now. This puts the doctrine in direct tension with any position that requires an ultimate, independently existing ground, whether a creator God, a substantial soul, purusha, or a monist Brahman, since dependent origination denies that anything, including the self, meets that description, a denial made explicit in the closely related doctrine of anatta.
Karma as causal law is the doctrine's specifically ethical application, tracking how intentional action functions as one especially significant kind of condition within the broader web of dependent arising, while dependent origination itself is the more general claim about how any phenomenon whatsoever comes to be; treating the two as identical, a common simplification, obscures how much more comprehensive the general principle is meant to be than its moral, karmic instance.