The design is the visual features of the COMBINED CUP AND INSULATING CUP SLEEVE shown in solid lines in the drawings, whether those features are features of one of shape, configuration, ornament or pattern or are a combination of any of these features. The portions shown in broken lines do not form part of the design.Fig. 1 is a perspective view of a design of a COMBINED CUP AND INSULATING CUP SLEEVE;Fig. 2 is a side elevation view thereof;Fig. 3 is a top view thereof;Fig. 4 is a bottom view thereof;Fig. 5 is a perspective view of a first variant of the design shown in Fig. 1;Fig. 6 is a side elevational; view of Fig. 5;Fig. 7 is a top view of Fig. 5; andFig. 8 is a bottom view of Fig. 5. Drawings of the design are included.