Dinamo Zagreb Sosa was born in the Prečko neighbourhood of
Zagreb to
Herzegovinian Croat parents from
Gradac, near
Posušje. He was a youth player for
Dinamo Zagreb. He was given his
Prva HNL debut for Dinamo by coach
Zoran Mamić on 7 March 2015 in a 2–0 home win over
Zagreb, starting and playing the full 90 minutes. On 10 May 2016, he played full 90 minutes in the
Croatian Cup Final as Dinamo defeated
Slaven Belupo 2–1. He made his European debut on 12 July 2016, when coach
Zlatko Kranjčar substituted him for
Alexandru Mățel in the 66th minute of the 2–1 victory over
Vardar in
Skopje in the
Champions League second qualifying round. Over the course of four seasons at Dinamo, Sosa made 41 appearances and six assists for his hometown club. He made his debut for Stuttgart on 26 August, after being substituted on for
Emiliano Insúa in the 84th minute of the 1–0 loss to
Mainz. However, due to frequent injuries, Sosa's minutes were significantly reduced in
his first season with Stuttgart, which saw the club relegated to the
2. Bundesliga. The injuries continued during
his second season as well, resulting in Sosa making only 24 appearances for Stuttgart in his first two seasons. However, the
2020–21 season was Sosa's breakthrough season, as he found form and consistency in
Pellegrino Matarazzo's 3–4–2–1
formation. His performances in the
Bundesliga earned him praise and comparisons to
David Beckham, whom he named his football role model alongside
David Alaba. On 27 November 2020, he extended his contract until 2025. He finished the season with nine assists on his account. At the beginning of the
2021–22 season, on 7 August, Sosa
captained Stuttgart for the first time in a
DFB-Pokal match against
Dynamo Berlin, scoring and assisting in the 6–0 victory. Seven days later, on the first matchday of
Bundesliga, Sosa provided
Marc-Oliver Kempf and
Hamadi Al Ghaddioui with a hat-trick of assists as Stuttgart defeated
Greuther Fürth 5–1.
Ajax On 1 September 2023, Sosa moved to
Eredivisie club
Ajax, signing a contract until 30 June 2028. He featured regularly at left-back during the
2023–24 season, under managers
Maurice Steijn and
John van 't Schip, making 25 appearances across the Eredivisie,
UEFA Europa League, and
UEFA Europa Conference League. He quickly established himself as a regular starter for Torino during the
2024–25 season, often playing as a
left wing-back. Sosa made a total of twenty appearances for Torino. Sosa provided zero assists and did not score any goals. At the end of the season, Torino decided not to exercise the option to buy the on-loan left-back.
Crystal Palace On 11 July 2025,
Premier League club
Crystal Palace announced the signing of Sosa on a three-year deal. On 10 August, he made his debut for the club as a second-half substitute against
Liverpool in the
FA Community Shield, which finished as a 2–2 draw; though Sosa missed his penalty in the ensuing shootout, he won his first trophy with Palace after they triumphed 3–2. On 2 October, he was sent off for a second yellow card in Palace's 2–0 away win over
Dynamo Kyiv in the
UEFA Conference League ==International career==