The much reduced uptake of A12-VHHkappa-IRDye800CW in the PD-L1 deficient tumors indicates that the MC38 tumor cells, rather than PD-L1-positive myeloid cells, are primarily responsible for the imaging agent’s uptake.Biodistribution analysis showed that A12-VHHkappa-IRDye800CW specifically accumulated in the tumor and not in other major organs (Fig. 4E), further supporting the suitability of the A12-VHHkappa conjugate for targeted delivery of various drugs to the tumor. This evidence concerns the gene CD274 and neoplasm.