CD68 and malignant colon neoplasm: Korehisa, S. et al. found that in patients with colon cancer with high microsatellite instability, PD-L1 is mainly expressed on aggressive front-end tumor cells and by CD68/CD163-positive M2 macrophages, and PD-L1 expression is accompanied by characteristics such as poor tumor differentiation, lymphatic invasion, and tumor budding [152].