https://screenrant.com/how-met-father-barney-cameo-daughter-himym-appearance/

How I Met Your Father season 2 will feature Barney Stinson's return, which could also include the full introduction of an important HIMYM character.

Barney in How I Met Your Father (https://www.looper.com/1315155/cameos-confusing-plot-holes/)

In 2022, Hilary Duff began starring in the spin-off series "How I Met Your Father." Indirectly related to its wildly successful parent series, "How I Met Your Mother," the show centers on Sophie, a woman in the year 2050 who recounts to her son the story of — you guessed it — how she met his father. But just because Sophie is an entirely new character and the series is set many years later doesn't mean there's no crossover with "How I Met Your Mother." In fact, a handful of characters from the original show have popped up, including Cobie Smulders as Robin Scherbatsky.

Robin — one-time wife of Barney Stinson on "How I Met Your Mother" — was once a pop star, but she eventually transitioned into a career as a news reporter. When she bumps into Sophie, she professes her adoration for Robin, whose life and career she's followed with great interest. That's all well and good, but later in the season Sophie also bumps into Barney via a minor fender bender. It's a nice moment for the audience to see an old face, but to Sophie, he's just another random motorist. Some have pointed out, though, that if she was so intimately familiar with the details of Robin's life, she maybe should have recognized her idol's ex-husband.