Fig. 2

Representative immunostaining of PD-L1, CD4 and CD8 in primary tumor a–c and paired liver metastatic tumor (d–f). a PD-L1 expression in primary tumor with a CPS score of 5.5; b CD4 density in primary tumor with a percentage of 40%; c CD8 density in primary tumor with a percentage of 22.5%; d PD-L1 expression in liver metastasis with a CPS score of 20; e CD4 density in liver metastasis with a percentage of 40%; f CD8 density in liver metastasis with a percentage of 20%