What planet is Bo-Katan Kryze drinking on when Din Djarin finds her in Baby Yoda was abducted by Moff Gideon, Mando has been gradually assembling a team of formidable fighters to launch a rescue mission. Having already recruited Boba Fett, Fennec Shand and Cara Dune, as well as using Migs Mayfeld to find Gideon's location, Djarin picks up another two - Bo-Katan Kryze and her companion, Koska Reeves. The two Mandalorians encountered each other on Trask in a previous episode, but didn't depart on the best due to Djarin's conflicting, cultist beliefs.
Mando and Boba Fett stroll into a bar, and recount Baby Yoda's plight to Bo-Katan and Koska. The clincher, however, comes when Moff Gideon's name is mentioned. Bo-Katan has been desperately seeking the Imperial villain to win back her Darksaber, and she agrees to the Baby Yoda rescue mission so long as Gideon is left to her. The group depart for Gideon's light cruiser with their Mandalorian contingent boosted considerably, but no character actually references the name of the planet during this scene.
Fortunately, there are a few clues as to Bo-Katan's location in The Mandalorian season 2's finale. As Slave I arrives, two moons are seen orbiting around the mystery planet. The surface is a mixture of mountainous terrain and green vegetation, but there are also plenty of factories and refineries dotted around. The bar is home to a mixture of different species, including Aqualish and Rodians, and the cantina has the vibe of an outer rim establishment. As a final (potential) clue, the shape of a Galactic Republic logo can be seen on a factory when Slave I lands, although the outline could also be an exhaust port of some kind.
Given all the information provided about this mystery planet, the best guess would perhaps be Lothal, a common setting in Slave I flies over. Lastly, the likes of Sabine Wren and Ezra Bridger were known to frequent Lothal in Star Wars Rebels. Wren was an ally of Bo-Katan's and even ed down the Darksaber to her. Lothal would certainly be a planet Bo-Katan might visit to let her guard down in the era of the New Republic.
Lothal certainly ticks all the boxes as the secret location in The Mandalorian's season 2 finale. Given how vital the planet is in Star Wars Rebels, however, The Mandalorian perhaps would've made a bigger deal out of Lothal's live-action debut, rather than slipping the planet in quietly. The Mandalorian season 2 has introduced plenty of new, previously unseen locales such as Trask and Corvus, and the planet where Bo-Katan Kryze s the rescue of Baby Yoda could be another fresh setting.