Tumors are a highly heterogeneous population with characteristics that normal cells do not have: unlimited replication, overactivation of new growth signals, and changes in the immune microenvironment. In-depth exploration of genomic differences between tumors and normal tissues can provide reference for clinical diagnosis and treatment. Bioinformatics analysis is now in full swing, and many public databases provide us with abundant transcriptome data and clinical information. By analyzing these data, we were able to identify new biomarkers to guide the diagnosis and treatment of tumors. Besides, bioinformatics analysis enables prognostic stratification, immune infiltration analysis, and even screening for potential mRNA vaccines. The purpose of this special issue is to provide new biomarkers for cancer through bioinformatics analysis.