In the present study, we comprehensively used multiple databases to analyze the relationship between STAT3 expression and prognosis, different stages of patients with pan-cancer, investigate the clinical value of STAT3 in predicting prognosis, and the relationship between STAT3 genetic alteration and prognosis, drug sensitivity, and STAT3 expression, to determine whether STAT3 participates in tumor immunity, to provide a rationale for STAT3 as a treatment for broad-spectrum malignancy. Here, STAT3 is linked to cancer.