RNA methylation is a post-transcriptional modification involving the addition of methyl groups to RNA molecules, playing a crucial role in gene expression regulation. Recent studies have highlighted the importance of RNA methylation, particularly N6-methyladenosine (m6A) modification, in cancer development and progression. RNA methylation affects mRNA stability, splicing, transport, and translation, thereby regulating various aspects of tumor cell biology, including proliferation, migration, and apoptosis. Abnormal RNA methylation patterns are closely linked to tumor aggressiveness and drug resistance, with dysregulation of methylation writers, erasers, and readers contributing to cancer onset and progression. Moreover, RNA methylation plays a significant role in cancer immunotherapy by influencing tumor cell immune evasion, offering new therapeutic targets. Future research should focus on elucidating the specific mechanisms of RNA methylation in different cancer types and its interactions with the tumor microenvironment. As technologies advance, RNA methylation modulators hold promising potential for cancer treatment, providing new strategies and therapeutic targets.