He then reemerged with a film crew to make the campaign video, in which he gave deeply misleading and potentially damaging advice to the American people about how to handle the worsening pandemic.
1.   reemerge 是不及物动词，意思“重新出现；再度出山”。reemerged with a film crew： 与一个电影摄制组再度出山。
2.  to make the campaign video：不定式作目的状语。意思是：制作竞选视频。也可以分析为 a film crew 的定语。意思是：制作竞选视频的摄制组。从整体意思看， 分析为定语不如目的状语有说服力。