Do not know whether these allegations are true or not, but an interesting possibility re last renewal of FISA warrant in 2017:

House Lawmakers Investigating Angela Merkel’s Meeting With Obama In Trump Probe

By Patrick Howley -Apr 18, 2018

"So Germany helped build the dossier. When does Merkel re-emerge in this picture?

“Fast forward to April/May 2017, roughly the same time the fourth and final FISA warrant was running out (because the Carter Page story was determined false). Rosenstein and McCabe were in desperate need of renewed help from intelligence to keep the Russian Collusion narrative alive,” Marler reports.

“Well they weren’t going to get help from the CIA because Pompeo was now CIA Director and wouldn’t help with a faux collusion narrative. In comes Obama to the rescue. He meets with Merkel in private (the US no longer monitored her communications because of the previous mishap) to beg for some more Sigint information to keep the collusion narrative alive. Conveniently he meets her hours prior to Trump’s meeting and his stay in her heavily monitored territory.”"

bigleaguepolitics.com/exclusive-house-lawmakers-investigating-angela-merkels-meeting-obama-trump-probe/