Neck and neck has 3 different meanings across 2 categories:
inconclusive as to outcome; close or just even in a race or comparison or competition
"as they approached the finish line they were neck and neck"
"the election was a nip and tuck affair"
very close in progress, as in a race or contest
even or close in a race or competition or comparison
"the horses ran neck and neck"
"he won nip and tuck"