Background: Patient-reported outcomes (PROs) are a primary tool to evaluate the effect of a given drug on the health-related quality of life from a patient’s perspective and to maximize the value of patient-centeredness in drug development and approval. In this study, we aimed to evaluate the current trend in reporting, analysis and interpretation of PRO data. Methods: We conducted a systematic review of the FDA archives, identifying all cancer immunotherapy drug approvals between the years 2011 and 2019. We then retrieved the clinical trials that respectively led to these drug approvals from PubMed and ClinicalTrials.gov. We systematically screened for PROs and assessed their analytic tools and interpretation methods that were collected from the published journal articles and their study protocols. If one FDA approval was supported by more than one clinical trial, we included all studies in our review. An FDA approval was considered to include PROs if they were reported in at least one of the supporting trials. Results: Thirty-seven clinical trials leading to 35 immunotherapy drug approvals were identified. More than half (54%) did not publish any PROs. While PROs were reported in the primary clinical outcomes manuscript of 4 trials (11%) and in a secondary separately published paper for 13 trials (35%). The median time between the primary and secondary papers was 22 months (range: 5 - 40). In the 17 published PROs, the hypothesis was broad in 12 (71%), not reported in 4 (24%) and specific in only 1 (6%). Ten (59%) were reported as exploratory endpoints, five (29%) as secondary endpoints, and two (12%) did not specify the PRO reporting in their endpoints. The most common PRO instruments were EQ-5D (71%) and QLQ-C30 (65%). Control for type I error was needed but not done in 15 (88%). Fourteen (82%) described an approach for dealing with missing PRO assessments. None reported on significant differences based on race and ethnicity of participants. Conclusions: Suboptimal reporting and delays in publication of PROs occur regularly in cancer immunotherapy trials. Increased efforts are needed to enhance standardization and quality reporting of PROs to maximize the value of this data in cancer immunotherapy drug approval.