The exchange of 64Cu by 68Ga led to a further reduced hepatobiliary uptake, and both [68Ga]Ga-NOTA-HACA-PD-1 and [68Ga]Ga-DOTA-HACA-PD-1 showed a highly specific tumor uptake and high tumor-to-muscle ratios at 1 h after injection (12.3 and 15.2, respectively). Here, PDCD1 is linked to neoplasm.