There’s still a few films that haven’t screened at Cannes (like the new one from Nuri Bilge Ceylan) but looks like these ones have had the most good buzz so far:
Cold War (Pawel Pawlikowski, director of Ida)
BlacKkKlansman (Spike Lee)
Happy as Lazzaro (Alice Rohrwacher, director of The Wonders)
Shoplifters (Hirokazu Kore-Eda, director of Nobody Knows, Still Walking etc)