However, there are many other causes for developing eosinophilia which can contribute to the difficulties in diagnosis and management.<h4>Case</h4>Here, we present a case of Strongyloides parasitic infection as an uncommon differential for eosinophilia in a patient with lung cancer receiving a PDL-1 ICI, durvalumab, in Australia.<h4>Conclusion</h4>This case highlights the complexities exploring the multiple potential causes of eosinophilia and the subsequent management, to allow safe continuation of ICI. Here, CD274 is linked to Increased total eosinophil count.