Cro-Magnons were just like us,

except the genes for
 blond hair [11 kya],
 blue eyes [10 kya] and
 pale skin [18 kya]
had not yet developed.

An obvious syllogism is:

Cro-Magnons were Haplogroup I

L-161 is Haplogroup I.

The L-161 are Cro-Magnons.

The term Cro-Magnon does not have a real definition and has fallen out of favor. It is used generally to refer to Anatomically Modern Humans (AMH) or Early European Modern Humans (EEMH) using the Mousterian or Aurignacian technology before the Gravettian technology was developed about 30,000 years ago.

Cro-Magnons began arriving in the Caucasus around 50,000 years ago. By 43,000 years ago, they had gone all the way to England. There were no other hominids except for Neanderthals. Cro-magnons began leaving archaeological evidence spread over the entire continent:
43,000 y.a. __Grotta del Cavallo in Liguria Italy.

43,000 y.a. __Kent's Cavern in England

42,000 y.a. __Pestera cu Oase cave in Romania near the 'Iron Gates'
The fossils in this cave show admixture with Neanderthals up to 50%.
40,000 y.a. __Mamontovaya Kurya in the Russian Arctic.

38,000 y.a. __Cro-Magnons developed the Aurignacian stone tool technology. In many of the locations, there was evidence of occupation by both Cro-Magnons and Neanderthals, though perhaps at separate times.

33,000 y.a. __Cro-Magnons domesticated dogs in Russia at the Kostyonki site.

32,000 y.a. __Cave paintings dating from the Aurignacian at Chauvet Cave in France.

and many others.

When they first arrived in Europe, Cro-Magnons were using the Acheulian tool technology. They met, and married, Neanderthals who were using the more advanced Mousterian technology. The Cro-Magnons soon learned the better Mousterian ways and then later improved on those by developing the Aurignacian technology.
Our modern European DNA is about 4% Neanderthal, so cohabiting did occur. It seems that the DNA percentage was much higher shortly after Cro-Magnons entered Europe, but has declined for at least two reasons. One is that continuing dilution from new migrants reduces the amount. Another is much more complicated. The DNA is eliminating itself. There may be several causes. The 'parts do not fit', so the DNA is selectively being eliminated. Or, there is evidence that there is some 'allergic reaction' that causes more spontaneous in-utero deaths. Or that the hybrids have low fertility. This is all under intense study.

A fictional, but probably realistic scenario is presented in Jean Auel's Earth's Children, an award-winning fiction series about a Cro-Magnon woman adopted into a Neanderthal tribe. An accompaniment to the Earth's Children books is a website Don's Maps by Don Hitchcock, an excellent collection of source and resource materials related to the archaeology of the time.