License for Company or Developer

I have an case like this.
I am the lead of product development in out company and 5 team members using unity developer. So, I should buy 5 license to my team member, isn’t it?
And then, when 1 of them go out from my company, is the license will be his?
Or, are there License for company?

The license is owned by the company, not the person. You need to buy one license per seat, that is, one per developer. Each developer can install it to two machines only: One desktop and one laptop, if he works from home sometimes.

There is no company-wide licensing options to my knowledge. But to be perfectly sure about these things, you really need to contact Unity Technologies about it instead of this Q&A board. This board is for technical questions to answered by your fellow users.