Generally speaking, you file a tax return for the state where your permanent home (domicile) is located, that reports and pays tax on all your world-wide income, regardless of where your employer is located.
You would be required to report income in Kansas (on a non-resident return) if you lived or physically worked in Kansas for part of the year. For example, if you attended 2 weeks of training in Kansas, then 2/52ths of your income would be Kansas income. Since you report all your income in Missouri, you can claim a tax credit if you paid tax to another state that will offset the Missouri tax on the same income.
There are 6 states that will try and tax remote workers based on where their employer is located, but Kansas is not one of them, so I won't dive any further into that messy situation.
