PDCD1 and neoplasm: Next, we hypothesized that CLEC‐1B, a C‐type lectin‐like receptor that is expressed on NK cells, could be a HRG receptor on NK cells based on previous reports suggesting a relationship between CLEC‐1B and tumor immunity.35 Due to an abundance of potential epitopes, we used human anti‐CLEC polyclonal antibodies to examine the effect of HRG on NK cell PD‐1 expression.