In colorectal tumor cells with MET expansion, the upregulation of PD-L1 expression aligns with the activation of the IFN-γ/STAT1 pathway, attributed to the increased phosphorylation of JAK1/2, facilitating STAT1 activation in response to IFN-γ stimulation and promoting the transcription of PD-L1. The gene discussed is IFNG; the disease is colorectal neoplasm.