Methods are provided for detecting the per cell programmed-death ligand 1 (PD-L1) expression of neoplasia cells. Aspects of the methods include cytometrically assaying a labeled cell suspension to quantify per cell PD-L1 expression to detect whether a neoplastic cell that expresses PD-L1 above a predetermined threshold is present in the neoplasia sample. In addition, kits that find use in practicing the subject methods are also provided.