OTUD1 and cancer: In this review, we comprehensively summarize the information available for OTUD1, an OTU family DUB, which participates in the regulation of cancer progression, antiviral signaling, innate and acquired immune responses, reactive oxygen species (ROS)-mediated oxidative damage through kelch-like ECH-associated protein 1 (KEAP1)-binding, and multiple related functions by cleaving diverse ubiquitin linkages.