The two are very different - Gemini is adventurous and what some would call crazy, whilst Cancer is more calm and prefers the comfort of his shell. Cancer will be attracted to the Gemini's intellect and sense of humor, while the latter will like former's sensitivity and passionate nature. However soon Cancer will start getting annoyed of Gemini's need for freedom, and Gemini will grow more restless of Cancer's jealousy and requests for commitment. A lot of adjustment is needed from both if this relationship is to work.