yes they are polar opposites, meaning that it could be an instant connection like in a soul mates kinda way or you could absolutely despise each other. opposites to me mean that one sign has traits that the other does not, and they make up for it in a way. and at the same time they’re learning from each other and growing as individuals and that’s very important to all relationships imo, if both are willing to work for it. for example, capricorns can be very closed off and concealing of their emotions (which is sometimes unhealthy) and from cancer they can learn to express themselves and embrace their emotions.