I claim the ornamental design for a cutting blade, as shown and described.
FIG. 1 is a perspective view of a cutting blade according to my new design;
FIG. 2 is a front elevation view thereof;
FIG. 3 is a rear elevation view thereof;
FIG. 4 is a left side elevation view thereof;
FIG. 5 is a right side elevation view thereof;
FIG. 6 is a top plan view thereof;
FIG. 7 is a bottom plan view thereto; and,
FIG. 8 is another perspective view thereof, shown in the environment of a cutting tool.
The broken lines showing portions of the cutting blade in FIGS. 1, 2, 3, and 8, and the tool in FIG. 8 are included for the purpose of showing portions of the cutting blade and its environment that form no part of the claimed design.