Karen's practice covers a broad spectrum, ranging from complex cross-border corporate and commercial litigation, white-collar crime, regulatory matters, shareholders disputes, shipping law, employment law, land disputes to judicial review. Apart from advising SOEs and multi-national clients, she also advises high net worth individuals and families in Hong Kong and China on a wide range of disputes, including contentious probate litigation and matrimonial proceedings.

Karen Cheung is based in the Hong Kong office and is also working closely with the BVI office.

Karen is also recognised in the Asian Legal Business' (ALB) annual "Asia Super 50 Disputes Lawyers", which profiles 50 of the most outstanding disputes lawyers in Asia in respect of client service. She is praised as being "professional, efficient" and "gives clients the confidence that they're being represented in the best possible manner" (ALB 2022). She was also short-listed as a finalist for Litigator of the Year (North Asia) in ALB Women in Law Awards 2021.

Karen is actively involved in community engagement as well. She is the founding Vice Chair of the Greater Bay Area Union and serves as the Chair of the Youth Committee of the Hong Kong and Mainland Legal Professional Association. She is trilingual in English, Putonghua and Cantonese. Karen is qualified in the Greater Bay Area and Hong Kong.

张嘉尹律师的业务范围广泛，从复杂的跨境民商事诉讼、白领犯罪、监管事宜、股东纠纷、航运法、雇佣法、土地纠纷到司法复核。除了国有企业和跨国企业外，她还为香港和国内的高净值个人及家庭的多种纠纷提供法律意见，包括有争议的遗嘱认证诉讼及婚姻诉讼。

张律师作为事务律师执业前曾是大律师。张律师拥有十多年的调解员经验，并作为大律师代表客户处理过在不同司法管辖区进行的仲裁，包括受HKIAC, ICC及LMAA规则管辖的仲裁及临时仲裁。张律师是英国特许仲裁司学会的资深会员和香港仲裁司学会的资深会员。

张律师亦荣膺《亚洲法律事务》本年度“亚洲五十佳争议解决律师”名单，该名单挑选出全亚洲客户服务最出色的50名律师。 客户对张律师评价包括“专业，高效”及“张律师作为我们的代理律师，用最佳的方式为我们的项目保驾护航，令我们充满信心”（亚洲法律事务2022）。张律师亦入围了2021《亚洲法律事务》法律杰出女性奖，年度诉讼律师（北亚）。

张律师也致力于社区活动。她是大湾区联合会的创始副会长，同时也是香港与内地法律专业联合会青年委员会主席。张律师精通英语、普通话和粤语三种语言。

此外，张律师拥有香港及大湾区执业资格。