Exeter will be looking to get out of the pool stages for only the second time in their history but face tough opposition from Glasgow, La Rochelle and Sale.
Exeter Chiefs
Best finish: Got through to the quarter-finals back in 2016 only to be beaten 25-24 by Premiership rivals Wasps.
What's hot: Exeter's work ethos and ability to get the best out of their players has been a major success for them. They enjoy playing with ball in hand and are a classy side who have big European ambitions.
What's not: While the Chiefs have soared in the Premiership, they have found Europe a very difficult nut to crack and the pressure is on. However, they go into the first round off the back of a loss that will have dented their confidence. They were 17-0 up against Bristol only to capitulate and fall to a 20-17 loss. Boss Rob Baxter will expect a better showing in Europe.
Key player Stuart Hogg. The disappointment of the 2019 World Cup will haunt Hogg for some time, but he has a chance to show his imperial skills on the fields of Europe. One of the best attacking full-backs in the game, Hogg should get plenty of opportunities to show what he can do with ball in hand. He can expect a warm welcome on his return to Scotstoun to face Glasgow in round 5.
Glasgow Warriors
Best finish: Have reached the last eight on two occasions but were beaten by Saracens both times. They lost 56-27 last season and 38-13 in 2017.
What's hot: After a slow start to the PRO14, the Warriors have got back to winning ways with a 50-point win over Southern kings followed by putting 30 points by Zebre.
What's Not: They have had a poor start to the PRO14 and have not exactly fired on all cylinders losing three of their first five games.
One to watch: Matt Fagerson. The 21-year-old flanker has already got 50 caps for Glasgow already and has a very promising future. Brings plenty of dynamism to their game as well as big defence.
La Rochelle
Best finish: The French club had a dream maiden Champions Cup season in 2017/18, topping Pool 1 before falling in the quarter-finals to the Scarlets.
What's hot: They have an impressive-looking squad who can do some real damage - the likes of Danny Priso and Thomas Jolmes bringing plenty of ballast up front. They also have some flair in the backs and the likes of flanker Victor Vito who can link the two. Ronan O'Gara has joined the coaching staff and brings plenty of European experience after his exploits with Munster.
What's Not: They are coming off a bit of a battering in the Top 14 after they came across high-flyers Lyon who beat them 45-17.
One to watch: Gregory Alldritt. The backrower was exceptional for La Rochelle in last year's Challenge Cup helping them reach the final. A massive ball carrier who has a nifty offload too - showed his worth for France in the World Cup too.
Sale Sharks
Best finish: Sale Sharks reached the quarter-finals of the European Cup in 2006 where they were beaten by 11-6 by Biarritz.
What's hot: After a two-year absence, Sale return to the European fold and will want to show that they belong here. They have plenty of depth in their squad and on paper look more than capable of competing on both fronts.
Their backrow combination is especially tasty with the Curry brothers, Mark Wilson, Dan and Jean-Luc Du Preez to choose from.
What's not: Away form has been a major concern for the Sharks - last season in the Premiership they only won twice on the road. They kick-off with a tough away fixture to Glasgow and Steve Diamond has made it clear he will be without World Cup stars Faf de Klerk, Tom Curry and Mark Wilson while Lood de Jager is recovering from the dislocated shoulder he suffered in the World Cup final.
Key player: Robert Du Preez. The fly-half is one of many of the classy South African contingent that Diamond has signed. Along with brothers Dan and Jean-Luc, Robert has taken well to playing in the Premiership. At 6ft 3 and just under 100kg, he is a big attacking fly-half who enjoys taking on the defence.