There is no legal marijuana trade in the US, as all marijuana trade is criminal under federal law, and it's generally a crime to knowingly profit from a crime (and, since drug offenses are covered in RICO, it's another crime to use any profits tired to them in the operation of any business engaged in interstate commerce.)
Microsoft may be keeping distant enough not to worry (though perhaps not given their formal partnership with Kind, even if their own offering is only to governments), but Kind is basically betting it's business -- and the personal liberty of its decision makers -- on the willingness of the federal government to extend the informal prosecutorial tolerance of in-state activities related to marijuana that comply with state laws in states which have adopted some form of state legalization to larger interstate enterprises (and on that tolerance continuing at all, which it might well not under a different administration.)
Microsoft may be keeping distant enough not to worry (though perhaps not given their formal partnership with Kind, even if their own offering is only to governments), but Kind is basically betting it's business -- and the personal liberty of its decision makers -- on the willingness of the federal government to extend the informal prosecutorial tolerance of in-state activities related to marijuana that comply with state laws in states which have adopted some form of state legalization to larger interstate enterprises (and on that tolerance continuing at all, which it might well not under a different administration.)