For example, AC-1, an antibody-based PROTAC termed AbTAC, simultaneously bound PD-L1 and E3 ligase RNF43 to degrade cell-surface PD-L1 via lysosomal degradation in different cell lines with high PD-L1 expression levels.1321,1322 Considering only a small fraction of cancer patients (lower than 50%) respond to PD-1/L1 inhibitors which are far from satisfactory, immune combination therapy which may improve the efficacy and expand the beneficiary population attracted much attention. Here, PDCD1 is linked to cancer.