Why did Wesker leave umbrella?

Why did Wesker leave umbrella? Wesker ultimately chose to betray Umbrella and work with other groups to steal its research data, benefiting from a mutation brought on by a prototype virus that gave him superhuman powers.

Wesker ultimately chose to betray Umbrella and work with other groups to steal its research data, benefiting from a mutation brought on by a prototype virus that gave him superhuman powers.