A Study to Investigate the Efficacy and Safety of an Infusion of IOV-4001 in Adult Participants With Unresectable or Metastatic Melanoma or Stage III or IV Non-small-cell Lung Cancer

This study is testing an experimental infusion therapy (IOV-4001) in adults with advanced melanoma or advanced non-small cell lung cancer (NSCLC) that has not responded to standard immunotherapy treatments. **You may be eligible if...** - You have been diagnosed with advanced or metastatic melanoma (stage IIIC, IIID, or IV), OR stage III–IV non-small cell lung cancer - For melanoma: your cancer progressed within 12 weeks of receiving an anti-PD-1/PD-L1 drug, and if your tumor has a BRAF mutation, you also tried a BRAF/MEK inhibitor - For NSCLC: you have received no more than 3 prior treatment lines - You are an adult **You may NOT be eligible if...** - You have active, untreated cancer in the brain - You have serious autoimmune conditions - You have significant heart, liver, or kidney problems - You are pregnant or breastfeeding Talk to your doctor to see if this trial is right for you.