The objective of this paper is to present a new perspective of tangent similarity measure of cubic spherical fuzzy sets. First, the concept of spherical fuzzy sets (SFSs) is extended to cubic spherical fuzzy notion. Then the fundamental concepts of Cubic-Spherical fuzzy sets (Cubic-SFSs) and their operations are studied. The idea of tangent similarity measure (TAN-SM) for Cubic-SFSs is introduced. Also some of the properties of TAN-SM are investigated numerically, and these concepts have been used to develop a new decision-making technique which will have influence in the field of decision science. Further, tangent fuzzy aggregation operator (TFAO) is introduced and a medical diagnosis intelligent system has been demonstrated based on the proposed MCDM approach. Finally, a sensitive analysis is conducted to show the efficiency of TAN-SM of Cubic-SFSs .