Because the absolute number of PD-L1 on cancer cells was not available from literature, PD-L1 density on cancer/immune cells in the tumor was estimated based on the in vitro measurement on mature dendritic cells and the percentage of tumor/immune cells (45%) that had concurrent PD-1 and PD-L1 expression in TNBC (Cheng et al., 2013; Gatalica et al., 2014; Wang et al., 2021). Here, PDCD1 is linked to cancer.