Compared with A549 xenograft tumor models, [68Ga]Ga-HN11-1, [68Ga]Ga-HN11-2 could markedly accumulate in the tumor sites of A549-PD-L2 xenograft tumor models at 60 min in Fig. 3D (n = 3), after blocking with excess of HN11-1 and HN11-2, tumor uptakes of [68Ga]Ga-HN11-1 and [68Ga]Ga-HN11-2 were decreased to 0.74 ± 0.03% and 0.82 ± 0.04%ID/g at 60 min, respectively (Fig. 3E). Here, PDCD1LG2 is linked to neoplasm.