CD274 and cancer: The immunoinhibitorymembrane protein programmed death ligand 1 (PD-L1) is highly expressedon certain tumor types, which masks malignant cells from T cell recognitionand creates an optimal environment for the cancer to thrive and spread.We report here a ligand-tetrazine conjugate (LTzC) armedwith a PD-L1 small molecule inhibitor to selectively target PD-L1-expressingcancer cells and inhibit PD-L1 function and conjugated to a tetrazinemodule and a lipoyl group to incorporate bioorthogonal reactivitiesand an oxidative stress enhancer into the construct.