Described herein are benzoxazepin oxazolidinone compounds with phosphoinositide-3 kinase (PI3K) modulation activity or function having the Formula I structure: or stereoisomers, tautomers, or pharmaceutically acceptable salts thereof, and with the substituents and structural features described herein. Also described are pharmaceutical compositions and medicaments that include the Formula I compounds, as well as methods of using such PI3K modulators, alone and in combination with other therapeutic agents, for treating diseases or conditions that are mediated or dependent upon PI3K dysregulation. Also described are methods of making the benzoxazepin oxazolidinone compounds having the Formula I structure.