CBSE and ICSE are national level education board in India.
While ICSE emphasises practical knowledge, the CBSE curriculum is more focused on theoretical principles.
While ICSE Board places equal weight on all academic streams, including Art, Language, Science, Mathematics, and even Humanities, CBSE places a strong emphasis on math and science.
While the CBSE board doesn't favour any language, ICSE boards place more focus on using English as the teaching language.