1. Telecoms deal: T-Mobile TMUS Sprint S

The agreement would leave just three major wireless carriers in the US.

The combined company, which will take on the name T-Mobile, would be positioned as a fierce competitor to Verizon (VZ) and AT&T (T). The deal, which follows years of deliberations, must still be approved by regulators.

T-Mobile CEO John Legere said he plans to hire thousands of people in a bid to create a nationwide network that will position the United States as the leader in 5G.

2. Walmart retreat: Shares in UK supermarket chain Sainsbury's jumped as much as 21% in London after the company said it would merge with Walmart's UK business Asda.

Walmart (WMT) will receive £2.97 billion ($4.1 billion) in cash and a 42% stake in the combined business. The deal values Asda at £7.3 billion ($10 billion), and creates a mega retailer with 2,800 stores and combined sales of roughly £51 billion ($70 billion).

Walmart could use the cash to fuel its expansion in other international markets. The US retailer is reportedly close to agreeing to invest in India's Flipkart, an online retailer that has also attracted attention from Amazon (AMZN).

3. WPP reports: The world's biggest advertising agency reported its first quarter results on Monday.

WPP (WPP) shares opened higher after the company revealed a sales slowdown that wasn't as bad as analysts had feared. WPP warned about the weaker advertising market earlier this year.

It's the company's first earnings report since veteran CEO Martin Sorrell resigned amid an investigation into alleged "personal misconduct." Sorrell, who led the business for the three decades, has denied any wrongdoing.

4. Global market overview: US stock futures were pointing higher.

European markets opened mixed, following a positive trading session in Asia. Markets in Shanghai and Tokyo were closed for holidays.

The Dow Jones industrial average closed 0.1% lower on Friday, while the S&P 500 added 0.1% and the Nasdaq was flat.

US crude oil futures dropped 1% to trade at $67.45 per barrel.

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5. Earnings and economics: Allergan (AGN) and McDonald's (MCD) will report earnings before the opening bell.

US personal income and personal spending data will be released by the Bureau of Economic Analysis at 8:30 a.m. ET.

Germany's inflation reading for March will be published at 8:00 a.m.

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6. Coming this week:

Monday — McDonald's (MCD) earnings

Tuesday — Aetna (AET), Apple (AAPL), Merck (MRK), Pfizer (PFE), Snap (SNAP) earnings; Fed meeting

Wednesday — CVS (CVS), Humana (HUM), Kraft Heinz (KHC), Metlife (MET), Molson Coors (TAP), Spotify (SPOT), Tesla (TSLA), Yum (YUMC); Fed meeting

Thursday — Cigna (CI), DowDuPont (DWDP), Kellogg (K), Weight Watchers (WTW) earnings

Friday — Alibaba (BABA), Newell Brands (NWL) earnings; Berkshire Hathaway annual shareholder weekend kicks off; Jobs report