1>selenium is an open source tool and TOSCA is vendor tool
2>selenium is only for web application and TOSCA use any like web , mobile etc.
3>Automation type:Selenium is purely code based and TOSCA is model based.
4>Scripting Language:Selenium required multiple scripting language and TOSCA is not used.
5>Test Data Management: TOSCA but selenium is not.
6>CI Integration: Selenium uses jenkin and TOSCA use any CI Tool.
7>QC/Jira Integration :TOSCA required but selenium not required