Generally, this is an opposition.But I think that you could be dealing with a different set of clashing priorities.
The Sag/Gem Moon individual may have to find a balance between passion and reason. Principle and flexibility etc.
This above Sun/ Moon combo is often a contradiction; on one hand they can be on a quest for universal principles and truth.(Sag).But they can get lost or bogged down by a love of rumors, gossip and hearsay (Gem)
They may want to learn about the world(Sag). But cling very much to the teachings of their childhood neighborhood(Gem).
The Sag/Cancer opposition may pull the individual in between wanting to venture "out there"(Sag), but being terrified of leaving the safety nest(Cancer).
What usually happens here are two things; either the person creates a haven/home (Cancer) wherever they go (Sag).
Or they dream/conceptualize about going to these places(Sag) without ever leaving their homeland(Cancer)
Whatever the outcome, it is likely that the person wants to balance the past, safety, security,emotional roots with their sense of adventure, expansion or intellectual growth.
Some may even teach (Sag) history(Cancer). Or they may try to understand the world(Sag) through looking at the patterns of the past(Cancer).