in the lead vs ahead

in the lead and ahead both are adjectives.

Word	Noun	Adjective	Verb	Adverb
in the lead	No	Yes	No	Yes
ahead	No	Yes	No	Yes

As adjectives, in the lead and ahead are synonyms defined as:

in the lead and ahead: having the leading position or higher score in a contest

Other synonyms of in the lead include leading.

As adverbs, in the lead and ahead are synonyms defined as:

Other synonyms of in the lead include out front.

in the lead (adjective)	ahead (adjective)
having the leading position or higher score in a contest	having the leading position or higher score in a contest

in the lead (adverb)	ahead (adverb)
leading or ahead in a competition	at or in the front
	ahead of time; in anticipation
	in a forward direction
	leading or ahead in a competition
	to a different or a more advanced time (meaning advanced either toward the present or toward the future)
	to a more advanced or advantageous position
	toward the future; forward in time