The United Explorer Card bonus offering 50,000 miles after the first purchase (and 10,000 more after $25k in spend in a year) has been around in some form (on and off) for a while, though either it has been targeted, or people have had to have some miles in their account to be able to view the deal.
All of that nonsense is gone (for now). Visit theexplorercard.com/60bonus to apply – it’s a non-affiliate, non-targeted link that is available to everyone. The offer is good through May 31st.
Remember that the United Explorer Card, which has the first year fee waived, offers free first checked bag, 2 club passes, and priority boarding.
A friendly reminder that you can generally apply for 1 Chase card every 30 days, and I suggest bundling your apps together so you’re waiting 90 days between apps.