i) Unbelievers say there's no evidence for the Exodus. Of course, the fact that we have a detailed account of the Exodus in the Pentateuch is prima facie evidence for the Exodus, even if you don't presume the inspiration of Scripture. Most of what we believe about historical events is based on historical testimony.
ii) But here's another consideration: on the face of it, we have multiple attestation for the Exodus. It isn't just the Pentateuch. The OT contains numerous references to the Exodus, viz. Jdg 6:8-9,13; 1 Sam 12:6,8; 1 Kgs 8:51; 2 Chron 7:22; Neh 9:9ff; Pss 77:14-20; 78:12-55; 80:8; 106:7-12; 114; Hos 11:1; Jer 7:21-24; 11:1-3; Dan 9:15.
iii) Now, unbelievers might try to argue that these are all secondary references. All literarily dependent on the Pentateuch. But there are problems with that claim:
a) It generates a dilemma: liberal scholars don't think the Pentateuch was written first.
b) If the Exodus happened, then that would be a part of family lore for descendants of the Exodus generation.
c) In addition, due to its religious significance, you'd have collective memory. There'd be a motivation to perpetuate those anecdotes.
d) Consider the Mormon Trek. Misguided followers of Brigham Young who accompanied him to the Salt Lake Valley. It wouldn't surprise me if anecdotes of that journey were passed down from one generation to the next.