OBJECTIVE: The aim of this work is to identify putative hub genes for the advancement of clear cell renal cell carcinoma (ccRCC) and determine the fundamental mechanisms. METHODS: We employed multiple bioinformatics techniques to screen hub genes. Key hub gene expression levels in ccRCC were assessed. A plethora of functional experiments were carried out to explore the biological role of hub gene. Based on genome-wide association studies, a Mendelian randomization research was conducted to ascertain the causative relationship between albumin (ALB) and ccRCC. RESULTS: ALB was low expression in ccRCC tissues and cell lines. It was an independent predictor of progression-free survival following treatment and the overall survival of ccRCC patients. ALB overexpression exhibited the reverse effects of ALB knockdown, which increased cell proliferation, migration, and invasion while inhibiting cell death. Similarly, ALB overexpression inhibited the growth of ccRCC tumors in vivo. Consistent with functional enrichment analysis, ALB overexpression activates the endoplasmic reticulum stress (ERS) in vitro and vivo. The Mendelian randomization showed ALB was associated with the risk of ccRCC. Additionally, ALB was causally associated with γδT cells infiltrates in ccRCC. CONCLUSION: ALB plays an important effect in ccRCC via activation of the ERS and regulating immune microenvironment.