That is not the type of injury we have previously found to be hypothetical. See Brooklyn Brewery Corp. v. Brooklyn Brew Shop, 17 F.4th 129, 139 (Fed. Cir. 2021) (concluding that a "possible injury" based on the use of a challenged mark in connection with sanitizing preparations was hypothetical where the appellant had no plan or interest in expanding its business to encompass sanitizing preparations).

"The appellant must also satisfy the requirements of Article III." Brooklyn Brewery Corp. v. Brooklyn Brew Shop , 17 F.4th 129, 137 (Fed. Cir. 2021) (emphasis added). "[A]lthough Article III standing is not necessarily a requirement to appear before an administrative agency [such as the TTAB], once a party seeks review in a federal court, ‘the constitutional requirement that it have standing kicks in.’ "

While Article III standing may not be waived, statutory standing arguments like those raised here are subject to different rules of waiver and forfeiture. See Brooklyn Brewery Corp. v. Brooklyn Brew Shop, 17 F.4th 129, 140 (Fed. Cir. 2021).

We review the board's application of the doctrine of laches for abuse of discretion. See Nuss v. OPM, 974 F.2d 1316, 1318 (Fed. Cir. 1992); see also Brooklyn Brewery Corp. v. Brooklyn Brew Shop, LLC, 17 F.4th 129, 142 (Fed. Cir. 2021).

The question whether a proposed mark is a source identifier typically arises before us in the context of whether the proposed mark is descriptive under 15 U.S.C. § 1052(e). E.g., Brooklyn Brewery Corp. v. Brooklyn Brew Shop , 17 F.4th 129 (Fed. Cir. 2021) ; In re Stereotaxis, Inc. , 429 F.3d 1039 (Fed. Cir. 2005). Our predecessor court recognized that the source identifier and descriptiveness inquiries are "complementary and opposite sides of the same coin to the extent that a mark ... is ‘merely descriptive’ of the goods."

Id. at 339; see Brooklyn Brewery Corp. v. Brooklyn Brew Shop, LLC, 17 F.4th 129, 138 (Fed. Cir. 2021) (stating that in a trademark action, a plaintiff establishes injury in fact if they “demonstrate a concrete and particularized risk of interference with the rights that flow to it from its [trademark] registration”).

As for constitutional standing, the defendants' claimed competitive injury is sufficient to state a constitutionally cognizable injury, as it typically is in a colorable trademark case based on alleged likelihood of confusion in allegedly overlapping fields. See Brooklyn Brewery Corp. v. Brooklyn Brew Shop, 17 F.4th 129, 139 (Fed. Cir. 2021). Wilfong's arguments regarding standing