Background: Recent evidence has emerged regarding the modification of the relationship between the enhancer RNA (eRNA) colorectal neoplasia differentially expressed (CRNDE) and the prognosis of patients with cancer. Nevertheless, the role of CRNDE in pan-cancer and tumour immune microenvironment (TIME) remains largely unexplored. Methods: Multiple bioinformatic methods were employed to unravel the role of elncRNA CRNDE in a wide range of cancers from the perspective of the expression patterns, prognosis, tumour immunity, and the association between CRNDE and its target gene IRX5 based on the public database. A nomogram was created by integrating independent factors. Gene set enrichment analysis (GSEA) was used to determine the potential signalling pathway mechanisms. Molecular biology experiments including RT-qPCR, MTT, Transwell, and wound-healing analyses were performed to evaluate the proliferation, migration, and invasion of glioma cells. Finally, RT-qPCR and immunohistochemistry were performed to analyse the expression and function of CRNDE in gliomas of different grades. Nissl staining was used to evaluate the potential effects of CRNDE knockdown in glioblastoma tissues. Results: CRNDE was dysregulated and associated with clinical features in 15 of the 33 cancer types. The survival analysis showed that high CRNDE expression might lead to a worsened prognosis among the six cancer types. CRNDE might be involved in immune regulation in multiple cancer types. CRNDE correlated with multiple tumours and immune-related pathways. Additionally, CRNDE knockdown inhibited glioma cell proliferation, migration, and invasion. Nissl staining confirmed that CRNDE siRNA notably decreased tumour growth. A stronger correlation between immune cells and CRNDE/IRX5 in lower-grade glioma than in glioblastoma multiforme tissues, and an association with IRX5 and immune checkpoint gene NRP1 were observed. Conclusions: An Enhancer RNA CRNDE may serve as a biomarker for cancer immunologic infiltration and poor prognosis, providing a new approach for cancer treatment.