The tournament has been won by an English club on 10 occasions since it was launched in 1995-96 under the previous name of the Heineken Cup.
Since Exeter Chiefs beat Racing 92 in the final at Ashton Gate in 2019-20, the trophy has been claimed by a French club in each of the subsequent four years, with no English finalists in that time.
Harlequins have never won the tournament in their history, while London rivals Saracens are the most successful English club in the competition with three titles, the last in 2019.
Sarries visit three-time champions Toulon in the last 16, while Sale Sharks face a trip to holders Toulouse.
Leicester Tigers visit Glasgow Warriors and Northampton host Clermont Auvergne at Franklin’s Gardens in the first of the last-16 ties.
Harlequins are currently sixth in the Premiership table, three points behind fourth-placed Leicester with seven matches remaining.
Care announced in January he would remain with Harlequins next season for his 20th year with the club.
He has won two Premiership titles with the club and said he would love to add to his collection before hanging up his boots.
“[I’m] Not [planning on playing for] much longer. I’m still really enjoying my rugby, I love the club, I always said I’d never pack it in until I didn’t feel I could help the team, or I wasn’t enjoying it,” he added.
“I’d love to help the club lift another trophy before I stop. Whether that be this year or next year, I’m not sure but I’ll try my best to help these young lads reach their goals and reach their dreams.”
