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 lung carcinoma.