STAT3 and neoplasm: Work in human THP-1 monocytic cells (where both mRNA and protein levels of PD-L1 were reduced with Hsp90 inhibitor treatment) suggested that this could be due to impaired transcription factor function (i.e., c-myc and Stat3) (Zavareh et al., 2021) but in the context of the tumour microenvironemnt, this could be due to the selection of PD-L1-independent tumour cell populations.