Tergenpumatucel‐L is a vaccine comprised of allogeneic NSCLC cells genetically modified to express a carbohydrate to which humans have pre‐existing immunity. The tryptophan mimetic indoximod may improve the efficacy of standard vaccination and chemotherapy by preventing IDO/TDO‐mediated immune suppression. Here, IDO1 is linked to non-small cell lung carcinoma.