ST6GAL1 and neoplasm: further confirmed that PD‐L1 is a highly N‐glycosylated protein with four N‐glycosylation sites, and that glycosylation protects PD‐L1 from ubiquitination and proteasome‐dependent degradation.[10] Our results also suggest that ST6GAL1 stabilizes PD‐L1 protein via α2,6‐sialylation, thereby preventing its proteasomal degradation and promoting an immunosuppressive tumor microenvironment.