Using T cells as an example, tumor cells can tune down T cell receptor (TCR)-mediated stimulatory signaling by downregulating surface MHC-I level.3 On the other hand, tumor cells can tune up PD-1-mediated inhibitory signaling by upregulating surface PD-L1 level.4 The concept that blocking the activation of inhibitory immunoreceptors can reinvigorate antitumor function of immune cells has been demonstrated experimentally and translated to treatment of many types of cancer in the clinic.5,6. Here, CD274 is linked to cancer.