HCG18 and melanoma: We revealed the importance of 4 mRNAs (FKBP4, RCC1, GBP 1, and PRADC1), 1 miRNA (hsa-mir-137), and 7 lncRNAs (HCP5, SNHG14, FGD5-AS1, HCG18, MAGI2-AS3, OIP5-AS1, and TUG1) in reshaping the immune microenvironment and regulating the melanoma process, providing new biomarkers for understanding the mechanism of melanoma occurrence and development at multiple levels, and promoting exploration of prognostic and therapeutic targets.