Candida albicans is a fungal pathogen able to colonize gastrointestinal (GI) track of mammalian hosts. The fungus, normally present as a commensal colonizer, can cause life-threatening infections when the host is immunocompromised. It was previously shown that the immune status of the host influences expression of EFG1 gene in C. albicans. Using evolutionary game theory approach we study the dynamic expression of this gene in C. albicans cells colonizing murine GI track. Our model, supported with experimental data, predicts that C. albicans ability to change Efg1 activity increases evolutionary fitness of the fungal population when exposed to a variable immune response.