Well the German elections just happened and CDU lost its dominance after more than 15 years. On the other hand, SPD came back in the first place for the first time in the last two decades. It holds the relative majority in the Bundestag, but a coalition is inevitable. Besides CDU's decline, AfD also declined and the power of Die Linke collapsed. On the other hand, those of FDP slightly improved and the Greens almost doubled their numbers. This points towards a ''street lights'' or ''Jamaica'' alliance (SPD/CDU, Greens, FDP), since Die Linke is too minor to be taken into consideration. This doesn't portray CDU in very bright colours, but it will at least not taint Merkel's reputation, who essentially retired from politics after 16 years of successful chancellorship.
I think the results reflect more the frustration of the Germans with CDU's way too long rule than a genuine resurrection of SPD. Germans simply grew tired of the Christian-Democratic government, whose popularity also suffered from the handling of the flood crisis in the west. The polarisation benefited SPD and undermined Die Linke, whose supporters voted for the center-left party, in order to finally get rid of the conservative administration. The Greens obviously absorbed a large portion of the CDU former voters, but I believe that AfD and FDP are also major losers in the elections. The situation was ideal for them, as the principal party in their political spectrum was losing influence and yet they barely profited from it. The decrease of AfD's popularity is rather embarrassing, considering how deeply the far-right has exploited the refugee and pandemic crises, but it is probably explained by the reduced importance of these issues in the public discourse. Coronavirus has been overtaken by climate change and immigration is nowadays as big of a concern as pensions and inequality.