The HCC827, MG-63, and NCI-H1650 cell lines—each with high natural expression of immune checkpoint proteins PD-L1, CD155, and B7-H3, respectively—were developed into an IFNγ-IFNγR JAK-STAT GAS-Luc2 reporter systems that are capable of reliably reporting the activity of IFNγ from activated primary human immune cells that mimic the in vivo cancer cell killing events. The gene discussed is CD274; the disease is cancer.