There is an interesting article in this season's American Ancestors using genetics and genealogy to determine if Lincoln and Lee were, indeed, related. The article describes Lee's DNA from current Lee male lines and Lincoln's DNA from descendants from Charles Lee's line.
The full citation is:
Hall, Richard. Testing a Theory: Were Abraham Lincoln and Robert E. Lee Related? Boston, MA: American Ancestors, Vol. 21, No. 4., Winter 2021. Pages 44-47.
The article was written to support or refute a story by William E. Barton published in the January 1929 Good Housekeeping magazine titled 'Abraham Lincoln Was a Lee.'
SPOILER ALERT: The haplogroup for Abraham Lincoln's William Lee descendants is R1b. The haplogroup for Gen. Robert E. Lee's Col. Richard Lee descendants is I1a.