Blend or harmonize.

synonyms: blend, go.

Roget 530: blend in, blend into the background.    lie in ambush etc. (hide oneself) 528; lie in wait for, lurk; set a trap for etc. (deceive) 545; ambuscade, ambush.    camouflage.    ... show more

Cause (something) to be mixed with (something else):
— At this stage of making the cake, blend in the nuts.

synonym: mix in.