SUMMARY ORDER

Appellant Juan Rullan, proceeding pro se, appeals the district court’s judgment dismissing his claims of employment discrimination and retaliation in violation of Title VII of the Civil Rights Act of 1964, 42 U.S.C. § 2000e, et seq., and the Americans with Disabilities Act, 42 U.S.C. § 12102, et seq. (“ADA”), and failure to accommodate under the ADA as barred by the principles of res judicata and collateral estoppel and as insufficient to state a claim for relief under Fed.R.Civ.P. 12(b)(6). We assume the parties’ familiarity with the underlying facts, the procedural history of the case, and the issues on appeal.

We review de novo a district court’s application of res judicata and collateral estoppel principles, Computer Assocs. Int’l, Inc. v. Altai, Inc., 126 F.3d 365, 368 (2d Cir. 1997), and its dismissal for failure to state a claim, Lucas v. United States, 775 F.3d 544, 547 (2d Cir. 2015) (per cu-riam). As an initial matter, because Rul-lan does not challenge on appeal any of the grounds on which the district court dismissed his complaint, those claims are abandoned. See LoSacco v. City of Mid- *87 dletown, 71 F.3d 88, 92-93 (2d Cir. 1995) (holding, in the context of a pro se appeal, that issues not raised in an appellate brief are abandoned). Even if Rullan had preserved any issues for appeal, however, an independent review of the record and relevant case law reveals that the district court properly dismissed his claims.

We have considered all of Rullan’s arguments and find them to be without merit. Accordingly, we AFFIRM the judgment of the district court.