The present disclosure provides human lipocalin muteins that bind CD137 and can be used in pharmaceutical applications, for example, as anti-cancer agents and/or immune modulators for the treatment or prevention of human diseases such as cancer, infectious diseases, and autoimmune diseases. The present disclosure also concerns methods of making CD137 binding lipocalin muteins described herein as well as compositions comprising such lipocalin muteins. The present disclosure further relates to nucleic acid molecules encoding such lipocalin muteins and to methods for generation of such lipocalin muteins and nucleic acid molecules. In addition, the application discloses therapeutic and/or diagnostic uses of these lipocalin muteins as well as compositions comprising one or more of such lipocalin muteins.
